April 2026 - dev

[PATCH v2] tcp: Handle errors from tcp_send_flag()
by Anshu Kumari 23 Apr '26

23 Apr '26

tcp_send_flag() can fail in two different ways: - tcp_prepare_flags() returns -ECONNRESET when getsockopt(TCP_INFO) fails: the socket is broken and the connection must be reset. - tcp_vu_send_flag() returns -EAGAIN when vu_collect() finds no available vhost-user buffers: this is a transient condition equivalent to a dropped packet on the wire. Have tcp_vu_send_flag() return -EAGAIN instead of a bare -1 for the buffer-unavailable case. Absorb -EAGAIN in the tcp_send_flag() dispatcher so that callers only see fatal errors. Check the return value at each call site and handle fatal errors: - in tcp_data_from_tap(), return -1 so the caller resets - in tcp_tap_handler(), goto reset - in tcp_timer_handler()/tcp_sock_handler()/tcp_conn_from_sock_finish(), call tcp_rst() and return - in tcp_tap_conn_from_sock(), set CLOSING flag, call FLOW_ACTIVATE() to avoid leaving the flow in TYPED state, and return - in tcp_connect_finish(), call tcp_rst() and return - in tcp_keepalive(), call tcp_rst() and continue the loop - in tcp_flow_migrate_target_ext(), goto fail The call in tcp_rst_do() is left unchecked: we are already resetting, and tcp_sock_rst() still needs to run regardless. Link: https://bugs.passt.top/show_bug.cgi?id=194 Signed-off-by: Anshu Kumari <anskuma(a)redhat.com> --- v2: - updated commit message. - update tcp_vu_send_flag() to return -EAGAIN instead of -1 for buffer-unavailable case. - in tcp_tap_conn_from_sock(), added FLOW_ACTIVATE call. - inside tcp_send_flag(), updated the return statement. function will return 0 incase of -EAGAIN error. --- tcp.c | 74 +++++++++++++++++++++++++++++++++++++++++--------------- tcp_vu.c | 6 +++-- 2 files changed, 59 insertions(+), 21 deletions(-) diff --git a/tcp.c b/tcp.c index 8ea9be8..28139d8 100644 --- a/tcp.c +++ b/tcp.c @@ -1378,15 +1378,19 @@ int tcp_prepare_flags(const struct ctx *c, struct tcp_tap_conn *conn, * @conn: Connection pointer * @flags: TCP flags: if not set, send segment only if ACK is due * - * Return: negative error code on connection reset, 0 otherwise + * Return: negative error code on fatal connection failure, 0 otherwise */ static int tcp_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags) { + int ret; + if (c->mode == MODE_VU) - return tcp_vu_send_flag(c, conn, flags); + ret = tcp_vu_send_flag(c, conn, flags); + else + ret = tcp_buf_send_flag(c, conn, flags); - return tcp_buf_send_flag(c, conn, flags); + return ret == -EAGAIN ? 0 : ret; } /** @@ -1917,7 +1921,9 @@ static int tcp_data_from_tap(const struct ctx *c, struct tcp_tap_conn *conn, "keep-alive sequence: %u, previous: %u", seq, conn->seq_from_tap); - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) + return -1; + tcp_timer_ctl(c, conn); if (setsockopt(conn->sock, SOL_SOCKET, SO_KEEPALIVE, @@ -2043,14 +2049,16 @@ eintr: * Then swiftly looked away and left. */ conn->seq_from_tap = seq_from_tap; - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) + return -1; } if (errno == EINTR) goto eintr; if (errno == EAGAIN || errno == EWOULDBLOCK) { - tcp_send_flag(c, conn, ACK | DUP_ACK); + if (tcp_send_flag(c, conn, ACK | DUP_ACK)) + return -1; return p->count - idx; } @@ -2070,7 +2078,8 @@ out: */ if (conn->seq_dup_ack_approx != (conn->seq_from_tap & 0xff)) { conn->seq_dup_ack_approx = conn->seq_from_tap & 0xff; - tcp_send_flag(c, conn, ACK | DUP_ACK); + if (tcp_send_flag(c, conn, ACK | DUP_ACK)) + return -1; } return p->count - idx; } @@ -2084,7 +2093,8 @@ out: conn_event(c, conn, TAP_FIN_RCVD); } else { - tcp_send_flag(c, conn, ACK_IF_NEEDED); + if (tcp_send_flag(c, conn, ACK_IF_NEEDED)) + return -1; } return p->count - idx; @@ -2122,7 +2132,10 @@ static void tcp_conn_from_sock_finish(const struct ctx *c, return; } - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) { + tcp_rst(c, conn); + return; + } /* The client might have sent data already, which we didn't * dequeue waiting for SYN,ACK from tap -- check now. @@ -2308,7 +2321,9 @@ int tcp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af, goto reset; } - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) + goto reset; + conn_event(c, conn, SOCK_FIN_SENT); return 1; @@ -2388,7 +2403,9 @@ int tcp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af, } conn_event(c, conn, SOCK_FIN_SENT); - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) + goto reset; + ack_due = 0; /* If we received a FIN, but the socket is in TCP_ESTABLISHED @@ -2436,8 +2453,10 @@ static void tcp_connect_finish(const struct ctx *c, struct tcp_tap_conn *conn) return; } - if (tcp_send_flag(c, conn, SYN | ACK)) + if (tcp_send_flag(c, conn, SYN | ACK)) { + tcp_rst(c, conn); return; + } conn_event(c, conn, TAP_SYN_ACK_SENT); conn_flag(c, conn, ACK_FROM_TAP_DUE); @@ -2478,7 +2497,12 @@ static void tcp_tap_conn_from_sock(const struct ctx *c, union flow *flow, conn->wnd_from_tap = WINDOW_DEFAULT; - tcp_send_flag(c, conn, SYN); + if (tcp_send_flag(c, conn, SYN)) { + conn_flag(c, conn, CLOSING); + FLOW_ACTIVATE(conn); + return; + } + conn_flag(c, conn, ACK_FROM_TAP_DUE); tcp_get_sndbuf(conn); @@ -2585,7 +2609,10 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref) return; if (conn->flags & ACK_TO_TAP_DUE) { - tcp_send_flag(c, conn, ACK_IF_NEEDED); + if (tcp_send_flag(c, conn, ACK_IF_NEEDED)) { + tcp_rst(c, conn); + return; + } tcp_timer_ctl(c, conn); } else if (conn->flags & ACK_FROM_TAP_DUE) { if (!(conn->events & ESTABLISHED)) { @@ -2598,7 +2625,10 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref) tcp_rst(c, conn); } else { flow_trace(conn, "SYN timeout, retry"); - tcp_send_flag(c, conn, SYN); + if (tcp_send_flag(c, conn, SYN)) { + tcp_rst(c, conn); + return; + } conn->retries++; conn_flag(c, conn, SYN_RETRIED); tcp_timer_ctl(c, conn); @@ -2662,8 +2692,11 @@ void tcp_sock_handler(const struct ctx *c, union epoll_ref ref, tcp_data_from_sock(c, conn); if (events & EPOLLOUT) { - if (tcp_update_seqack_wnd(c, conn, false, NULL)) - tcp_send_flag(c, conn, ACK); + if (tcp_update_seqack_wnd(c, conn, false, NULL) && + tcp_send_flag(c, conn, ACK)) { + tcp_rst(c, conn); + return; + } } return; @@ -2903,7 +2936,8 @@ static void tcp_keepalive(struct ctx *c, const struct timespec *now) if (conn->tap_inactive) { flow_dbg(conn, "No tap activity for least %us, send keepalive", KEEPALIVE_INTERVAL); - tcp_send_flag(c, conn, KEEPALIVE); + if (tcp_send_flag(c, conn, KEEPALIVE)) + tcp_rst(c, conn); } /* Ready to check fot next interval */ @@ -3926,7 +3960,9 @@ int tcp_flow_migrate_target_ext(struct ctx *c, struct tcp_tap_conn *conn, int fd if (tcp_set_peek_offset(conn, peek_offset)) goto fail; - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) + goto fail; + tcp_data_from_sock(c, conn); if ((rc = tcp_epoll_ctl(conn))) { diff --git a/tcp_vu.c b/tcp_vu.c index dc0e17c..9d63a30 100644 --- a/tcp_vu.c +++ b/tcp_vu.c @@ -65,7 +65,9 @@ static size_t tcp_vu_hdrlen(bool v6) * @conn: Connection pointer * @flags: TCP flags: if not set, send segment only if ACK is due * - * Return: negative error code on connection reset, 0 otherwise + * Return: -ECONNRESET on fatal connection error, + * -EAGAIN if vhost-user buffers are unavailable, + * 0 otherwise */ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags) { @@ -91,7 +93,7 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags) &flags_iov[0], 1, NULL, MAX(hdrlen + sizeof(*opts), ETH_ZLEN + VNET_HLEN), NULL); if (elem_cnt != 1) - return -1; + return -EAGAIN; assert(flags_elem[0].in_num == 1); assert(flags_elem[0].in_sg[0].iov_len >= -- 2.53.0

1 0

[PATCH] tcp: Use SO_MEMINFO for accurate send buffer overhead accounting
by Jon Maloy 22 Apr '26

22 Apr '26

The TCP window advertised to the guest/container must balance two competing needs: large enough to trigger kernel socket buffer auto-tuning, but not so large that sendmsg() partially fails, causing retransmissions. The current approach uses the difference (SNDBUF_GET() - SIOCOUTQ), but these values are in reality representing different units: SO_SNDBUF includes the buffer overhead (sk_buff head, alignment, skb_shared_info), while SIOCOUTQ only returns the actual payload bytes. The clamped_scale value of 75% is a rough approximation of this overhead, but it is inaccurate: too generous for large buffers, causing retransmissions at higher RTTs, and too conservative for small ones, hence inhibiting auto-tuning. We now introduce the use of SO_MEMINFO to obtain SK_MEMINFO_SNDBUF and SK_MEMINFO_WMEM_QUEUED from the kernel. Those are both presented in the kernel's own accounting units, i.e. including the per-skb overhead, and match exactly what the kernel's own sk_stream_memory_free() function is using. When we combine the above with the payload bytes indicated by SIOCOUTQ, the observed overhead ratio self-calibrates to whatever gso_segs, cache line size, and sk_buff layout the kernel may use, and is even architecture agnostic. When data is queued and the overhead ratio is observable (wmem_queued > sendq), the available payload window is calculated as: (sk_sndbuf - wmem_queued) * sendq / wmem_queued When the ratio cannot be observed, e.g. because the queue is empty or we are in a transient state, we fall back to 75% of remaining buffer capacity, like before. If SO_MEMINFO is unavailable, we fall back to the pre-existing SNDBUF_GET() - SIOCOUTQ calculation. Link: https://bugs.passt.top/show_bug.cgi?id=138 Signed-off-by: Jon Maloy <jmaloy(a)redhat.com> --- tcp.c | 33 ++++++++++++++++++++++++++------- util.c | 1 + 2 files changed, 27 insertions(+), 7 deletions(-) diff --git a/tcp.c b/tcp.c index 43b8fdb..3b47a3b 100644 --- a/tcp.c +++ b/tcp.c @@ -295,6 +295,7 @@ #include <arpa/inet.h> #include <linux/sockios.h> +#include <linux/sock_diag.h> #include "checksum.h" #include "util.h" @@ -1128,19 +1129,37 @@ int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn, new_wnd_to_tap = tinfo->tcpi_snd_wnd; } else { unsigned rtt_ms_ceiling = DIV_ROUND_UP(tinfo->tcpi_rtt, 1000); + uint32_t mem[SK_MEMINFO_VARS]; + socklen_t mem_sl; uint32_t sendq; - int limit; + uint32_t sndbuf; + uint32_t limit; if (ioctl(s, SIOCOUTQ, &sendq)) { debug_perror("SIOCOUTQ on socket %i, assuming 0", s); sendq = 0; } tcp_get_sndbuf(conn); + sndbuf = SNDBUF_GET(conn); - if ((int)sendq > SNDBUF_GET(conn)) /* Due to memory pressure? */ - limit = 0; - else - limit = SNDBUF_GET(conn) - (int)sendq; + mem_sl = sizeof(mem); + if (getsockopt(s, SOL_SOCKET, SO_MEMINFO, &mem, &mem_sl)) { + if (sendq > sndbuf) + limit = 0; + else + limit = sndbuf - sendq; + } else { + uint32_t sb = mem[SK_MEMINFO_SNDBUF]; + uint32_t wq = mem[SK_MEMINFO_WMEM_QUEUED]; + + if (wq > sb) + limit = 0; + else if (!sendq || wq <= sendq) + limit = (sb - wq) * 3 / 4; + else + limit = (uint64_t)(sb - wq) * + sendq / wq; + } /* If the sender uses mechanisms to prevent Silly Window * Syndrome (SWS, described in RFC 813 Section 3) it's critical @@ -1168,11 +1187,11 @@ int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn, * but we won't send enough to fill one because we're stuck * with pending data in the outbound queue */ - if (limit < MSS_GET(conn) && sendq && + if (limit < (unsigned int)MSS_GET(conn) && sendq && tinfo->tcpi_last_data_sent < rtt_ms_ceiling * 10) limit = 0; - new_wnd_to_tap = MIN((int)tinfo->tcpi_snd_wnd, limit); + new_wnd_to_tap = MIN(tinfo->tcpi_snd_wnd, limit); } new_wnd_to_tap = MIN(new_wnd_to_tap, MAX_WINDOW); diff --git a/util.c b/util.c index 73c9d51..036fac1 100644 --- a/util.c +++ b/util.c @@ -1137,3 +1137,4 @@ long clamped_scale(long x, long y, long lo, long hi, long f) return x - (x * (y - lo) / (hi - lo)) * (100 - f) / 100; } + -- 2.52.0

2 1

[PATCH v4 00/17] RFC: Dynamic configuration update implementation
by David Gibson 21 Apr '26

21 Apr '26

Here's the next draft of dynamic configuration updates. This now can successfully update rules, though I've not tested it very extensively. Patches 1..7/17 are preliminary reworks that make sense even without pesto - feel free to apply if you're happy with them. I don't think the rest should be applied yet; we need to at least harden it so passt can't be blocked indefinitely by a client which sends a partial update then waits. Based on my earlier series reworking static checking invocation. TODO: - Have pestos connecting to passt which already have a client attached block, instead of being rejected - Don't allow a client which sends a partial configuration then blocks also block passt - Allow pesto to clear existing configuration, not just add - Allow pesto selectively delete existing rules, not just add Changes in v4: * Merged with remainder of forward rule parsing rework series * Fix some bugs in rule checking pointed out by Laurent * Significantly cleaned up option parsing code * Changed from replacing all existing rules to adding new rules (clear and remove still TBD) * Somewhat simplified protocol (pif names and rules sent in a single pass) * pesto is now allocation free * Fixed commit message and style nits pointed out by Stefano Changes in v3: * Removed already applied ASSERT() rename * Renamed serialisation functions * Incorporated Stefano's extensions, reworked and fixed * Several additional cleanups / preliminary reworks Changes in v2: * Removed already applied cleanups * Reworked assert() patch to handle -DNDEBUG properly * Numerous extra patches: * Factored out serialisation helpers and use them for migration as well * Reworked to allow ip.[ch] and inany.[ch] to be shared with pesto * Reworks to share some forwarding rule datatypes with pesto * Implemented sending pif names and current ruleset to pesto David Gibson (17): conf, fwd: Stricter rule checking in fwd_rule_add() fwd_rule: Move ephemeral port probing to fwd_rule.c fwd, conf: Move rule parsing code to fwd_rule.[ch] fwd_rule: Move conflict checking back within fwd_rule_add() fwd: Generalise fwd_rules_info() pif: Limit pif names to 128 bytes fwd_rule: Fix some format specifiers pesto: Introduce stub configuration tool pesto, log: Share log.h (but not log.c) with pesto tool pesto, conf: Have pesto connect to passt and check versions pesto: Expose list of pifs to pesto and optionally display ip: Prepare ip.[ch] for sharing with pesto tool inany: Prepare inany.[ch] for sharing with pesto tool pesto: Read current ruleset from passt/pasta and optionally display it pesto: Parse and add new rules from command line pesto, conf: Send updated rules from pesto back to passt/pasta conf, fwd: Allow switching to new rules received from pesto .gitignore | 2 + Makefile | 54 +++-- common.h | 122 ++++++++++ conf.c | 672 +++++++++++++++++++++------------------------------ conf.h | 2 + epoll_type.h | 4 + flow.c | 4 +- fwd.c | 169 ++++--------- fwd.h | 41 +--- fwd_rule.c | 603 ++++++++++++++++++++++++++++++++++++++++++--- fwd_rule.h | 66 ++++- inany.c | 19 +- inany.h | 17 +- ip.c | 56 +---- ip.h | 4 +- lineread.c | 2 +- log.h | 59 ++++- passt.1 | 5 + passt.c | 8 + passt.h | 8 + pesto.1 | 46 ++++ pesto.c | 470 +++++++++++++++++++++++++++++++++++ pesto.h | 55 +++++ pif.c | 2 +- pif.h | 8 +- serialise.c | 7 + serialise.h | 1 + siphash.h | 13 + tap.c | 52 ++++ util.h | 110 +-------- 30 files changed, 1889 insertions(+), 792 deletions(-) create mode 100644 common.h create mode 100644 pesto.1 create mode 100644 pesto.c create mode 100644 pesto.h -- 2.53.0

1 17

[PATCH v5 00/18] RFC: Dynamic configuration update implementation
by David Gibson 21 Apr '26

21 Apr '26

Here's the next draft of dynamic configuration updates. This now can successfully update rules, though I've not tested it very extensively. Patches 1..8/18 are preliminary reworks that make sense even without pesto - feel free to apply if you're happy with them. I don't think the rest should be applied yet; we need to at least harden it so passt can't be blocked indefinitely by a client which sends a partial update then waits. Based on my earlier series reworking static checking invocation. TODO: - Don't allow a client which sends a partial configuration then blocks also block passt - Allow pesto to clear existing configuration, not just add - Allow pesto selectively delete existing rules, not just add Changes in v5: * If multiple clients connect at once, they're now blocked until the first one finishes, instead of later ones being discarded Changes in v4: * Merged with remainder of forward rule parsing rework series * Fix some bugs in rule checking pointed out by Laurent * Significantly cleaned up option parsing code * Changed from replacing all existing rules to adding new rules (clear and remove still TBD) * Somewhat simplified protocol (pif names and rules sent in a single pass) * pesto is now allocation free * Fixed commit message and style nits pointed out by Stefano Changes in v3: * Removed already applied ASSERT() rename * Renamed serialisation functions * Incorporated Stefano's extensions, reworked and fixed * Several additional cleanups / preliminary reworks Changes in v2: * Removed already applied cleanups * Reworked assert() patch to handle -DNDEBUG properly * Numerous extra patches: * Factored out serialisation helpers and use them for migration as well * Reworked to allow ip.[ch] and inany.[ch] to be shared with pesto * Reworks to share some forwarding rule datatypes with pesto * Implemented sending pif names and current ruleset to pesto David Gibson (18): conf, fwd: Stricter rule checking in fwd_rule_add() fwd_rule: Move ephemeral port probing to fwd_rule.c fwd, conf: Move rule parsing code to fwd_rule.[ch] fwd_rule: Move conflict checking back within fwd_rule_add() fwd: Generalise fwd_rules_info() pif: Limit pif names to 128 bytes fwd_rule: Fix some format specifiers tap, repair: Use SOCK_NONBLOCK and SOCK_CLOEXEC on Unix sockets pesto: Introduce stub configuration tool pesto, log: Share log.h (but not log.c) with pesto tool pesto, conf: Have pesto connect to passt and check versions pesto: Expose list of pifs to pesto and optionally display ip: Prepare ip.[ch] for sharing with pesto tool inany: Prepare inany.[ch] for sharing with pesto tool pesto: Read current ruleset from passt/pasta and optionally display it pesto: Parse and add new rules from command line pesto, conf: Send updated rules from pesto back to passt/pasta conf, fwd: Allow switching to new rules received from pesto .gitignore | 2 + Makefile | 54 ++-- common.h | 122 +++++++++ conf.c | 686 ++++++++++++++++++++++----------------------------- conf.h | 2 + epoll_type.h | 4 + flow.c | 4 +- fwd.c | 169 ++++--------- fwd.h | 41 +-- fwd_rule.c | 603 ++++++++++++++++++++++++++++++++++++++++++-- fwd_rule.h | 66 ++++- inany.c | 19 +- inany.h | 17 +- ip.c | 56 +---- ip.h | 4 +- lineread.c | 2 +- log.h | 59 ++++- passt.1 | 5 + passt.c | 8 + passt.h | 8 + pesto.1 | 46 ++++ pesto.c | 470 +++++++++++++++++++++++++++++++++++ pesto.h | 55 +++++ pif.c | 2 +- pif.h | 8 +- repair.c | 9 +- serialise.c | 7 + serialise.h | 1 + siphash.h | 13 + tap.c | 64 ++++- util.c | 2 +- util.h | 110 +-------- 32 files changed, 1921 insertions(+), 797 deletions(-) create mode 100644 common.h create mode 100644 pesto.1 create mode 100644 pesto.c create mode 100644 pesto.h -- 2.53.0

1 14

[PATCH v5 04/18] fwd_rule: Move conflict checking back within fwd_rule_add()
by David Gibson 21 Apr '26

21 Apr '26

2bffb631d31e ("fwd_rule: Move rule conflict checking from fwd_rule_add() to caller") moved rule conflict checking out of fwd_rule_add(). This seemed like a good idea at the time, but turns out to be kind of awkward: it means we're now checking for conflicts *before* we've checked the rule for internal consistency (including first <= last), which leaves an awkward assert() which might fire in unexpected places. While it's true that it's not really necessary to include this in order to safely add a rule, the benefits from skipping it are pretty marginal. So, for simplicity, fold this check back into fwd_rule_add(), making it non-fatal. If we ever have cases with enough rules that the O(n^2) nature of the check matters, we might need to revisit. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> Reviewed-by: Laurent Vivier <lvivier(a)redhat.com> --- fwd_rule.c | 38 +++++++++++++------------------------- 1 file changed, 13 insertions(+), 25 deletions(-) diff --git a/fwd_rule.c b/fwd_rule.c index cd3dec04..1413584f 100644 --- a/fwd_rule.c +++ b/fwd_rule.c @@ -195,29 +195,6 @@ static bool fwd_rule_conflicts(const struct fwd_rule *a, const struct fwd_rule * return true; } -/** - * fwd_rule_conflict_check() - Die if given rule conflicts with any in list - * @new: New rule - * @rules: Existing rules against which to test - * @count: Number of rules in @rules - */ -static void fwd_rule_conflict_check(const struct fwd_rule *new, - const struct fwd_rule *rules, size_t count) -{ - unsigned i; - - for (i = 0; i < count; i++) { - char newstr[FWD_RULE_STRLEN], rulestr[FWD_RULE_STRLEN]; - - if (!fwd_rule_conflicts(new, &rules[i])) - continue; - - die("Forwarding configuration conflict: %s versus %s", - fwd_rule_fmt(new, newstr, sizeof(newstr)), - fwd_rule_fmt(&rules[i], rulestr, sizeof(rulestr))); - } -} - /** * fwd_rule_add() - Validate and add a rule to a forwarding table * @fwd: Table to add to @@ -230,7 +207,7 @@ static int fwd_rule_add(struct fwd_table *fwd, const struct fwd_rule *new) /* Flags which can be set from the caller */ const uint8_t allowed_flags = FWD_WEAK | FWD_SCAN | FWD_DUAL_STACK_ANY; unsigned num = (unsigned)new->last - new->first + 1; - unsigned port; + unsigned port, i; if (new->first > new->last) { warn("Rule has invalid port range %u-%u", @@ -293,6 +270,18 @@ static int fwd_rule_add(struct fwd_table *fwd, const struct fwd_rule *new) return -EINVAL; } + for (i = 0; i < fwd->count; i++) { + char newstr[FWD_RULE_STRLEN], rulestr[FWD_RULE_STRLEN]; + + if (!fwd_rule_conflicts(new, &fwd->rules[i])) + continue; + + warn("Forwarding configuration conflict: %s versus %s", + fwd_rule_fmt(new, newstr, sizeof(newstr)), + fwd_rule_fmt(&fwd->rules[i], rulestr, sizeof(rulestr))); + return -EEXIST; + } + if (fwd->count >= ARRAY_SIZE(fwd->rules)) { warn("Too many rules (maximum %u)", ARRAY_SIZE(fwd->rules)); return -ENOSPC; @@ -435,7 +424,6 @@ static void fwd_rule_range_except(struct fwd_table *fwd, uint8_t proto, rule.last = i - 1; rule.to = base + delta; - fwd_rule_conflict_check(&rule, fwd->rules, fwd->count); if (fwd_rule_add(fwd, &rule) < 0) goto fail; -- 2.53.0

1 0

[PATCH v5 03/18] fwd, conf: Move rule parsing code to fwd_rule.[ch]
by David Gibson 21 Apr '26

21 Apr '26

The code parsing command line options into forwarding rules has now been decoupled from most of passt/pasta's internals. This is good, because we'll soon want to share it with a configuration update client. Make the next step by moving this code into fwd_rule.[ch]. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> Reviewd-by: Laurent Vivier <lvivier(a)redhat.com> --- conf.c | 376 +------------------------------------------ fwd.c | 94 ----------- fwd.h | 33 ---- fwd_rule.c | 464 ++++++++++++++++++++++++++++++++++++++++++++++++++++- fwd_rule.h | 36 ++++- 5 files changed, 502 insertions(+), 501 deletions(-) diff --git a/conf.c b/conf.c index b470b0d8..5aacfe0f 100644 --- a/conf.c +++ b/conf.c @@ -13,7 +13,6 @@ */ #include <arpa/inet.h> -#include <ctype.h> #include <errno.h> #include <fcntl.h> #include <getopt.h> @@ -66,365 +65,6 @@ const char *pasta_default_ifn = "tap0"; -/** - * port_range() - Represents a non-empty range of ports - * @first: First port number in the range - * @last: Last port number in the range (inclusive) - * - * Invariant: @last >= @first - */ -struct port_range { - in_port_t first, last; -}; - -/** - * parse_port_range() - Parse a range of port numbers '<first>[-<last>]' - * @s: String to parse - * @endptr: Update to the character after the parsed range (similar to - * strtol() etc.) - * @range: Update with the parsed values on success - * - * Return: -EINVAL on parsing error, -ERANGE on out of range port - * numbers, 0 on success - */ -static int parse_port_range(const char *s, const char **endptr, - struct port_range *range) -{ - unsigned long first, last; - char *ep; - - last = first = strtoul(s, &ep, 10); - if (ep == s) /* Parsed nothing */ - return -EINVAL; - if (*ep == '-') { /* we have a last value too */ - const char *lasts = ep + 1; - last = strtoul(lasts, &ep, 10); - if (ep == lasts) /* Parsed nothing */ - return -EINVAL; - } - - if ((last < first) || (last >= NUM_PORTS)) - return -ERANGE; - - range->first = first; - range->last = last; - *endptr = ep; - - return 0; -} - -/** - * parse_keyword() - Parse a literal keyword - * @s: String to parse - * @endptr: Update to the character after the keyword - * @kw: Keyword to accept - * - * Return: 0, if @s starts with @kw, -EINVAL if it does not - */ -static int parse_keyword(const char *s, const char **endptr, const char *kw) -{ - size_t len = strlen(kw); - - if (strlen(s) < len) - return -EINVAL; - - if (memcmp(s, kw, len)) - return -EINVAL; - - *endptr = s + len; - return 0; -} - -/** - * conf_ports_range_except() - Set up forwarding for a range of ports minus a - * bitmap of exclusions - * @fwd: Forwarding table to be updated - * @proto: Protocol to forward - * @addr: Listening address - * @ifname: Listening interface - * @first: First port to forward - * @last: Last port to forward - * @exclude: Bitmap of ports to exclude (may be NULL) - * @to: Port to translate @first to when forwarding - * @flags: Flags for forwarding entries - */ -static void conf_ports_range_except(struct fwd_table *fwd, uint8_t proto, - const union inany_addr *addr, - const char *ifname, - uint16_t first, uint16_t last, - const uint8_t *exclude, uint16_t to, - uint8_t flags) -{ - struct fwd_rule rule = { - .addr = addr ? *addr : inany_any6, - .ifname = { 0 }, - .proto = proto, - .flags = flags, - }; - char rulestr[FWD_RULE_STRLEN]; - unsigned delta = to - first; - unsigned base, i; - - if (!addr) - rule.flags |= FWD_DUAL_STACK_ANY; - if (ifname) { - int ret; - - ret = snprintf(rule.ifname, sizeof(rule.ifname), - "%s", ifname); - if (ret <= 0 || (size_t)ret >= sizeof(rule.ifname)) - die("Invalid interface name: %s", ifname); - } - - for (base = first; base <= last; base++) { - if (exclude && bitmap_isset(exclude, base)) - continue; - - for (i = base; i <= last; i++) { - if (exclude && bitmap_isset(exclude, i)) - break; - } - - rule.first = base; - rule.last = i - 1; - rule.to = base + delta; - - fwd_rule_conflict_check(&rule, fwd->rules, fwd->count); - if (fwd_rule_add(fwd, &rule) < 0) - goto fail; - - base = i - 1; - } - return; - -fail: - die("Unable to add rule %s", - fwd_rule_fmt(&rule, rulestr, sizeof(rulestr))); -} - -/* - * for_each_chunk - Step through delimited chunks of a string - * @p_: Pointer to start of each chunk (updated) - * @ep_: Pointer to end of each chunk (updated) - * @s_: String to step through - * @sep_: String of all allowed delimiters - */ -#define for_each_chunk(p_, ep_, s_, sep_) \ - for ((p_) = (s_); \ - (ep_) = (p_) + strcspn((p_), (sep_)), *(p_); \ - (p_) = *(ep_) ? (ep_) + 1 : (ep_)) - -/** - * conf_ports_spec() - Parse port range(s) specifier - * @fwd: Forwarding table to be updated - * @proto: Protocol to forward - * @addr: Listening address for forwarding - * @ifname: Interface name for listening - * @spec: Port range(s) specifier - */ -static void conf_ports_spec(struct fwd_table *fwd, uint8_t proto, - const union inany_addr *addr, const char *ifname, - const char *spec) -{ - uint8_t exclude[PORT_BITMAP_SIZE] = { 0 }; - bool exclude_only = true; - const char *p, *ep; - uint8_t flags = 0; - unsigned i; - - if (!strcmp(spec, "all")) { - /* Treat "all" as equivalent to "": all non-ephemeral ports */ - spec = ""; - } - - /* Parse excluded ranges and "auto" in the first pass */ - for_each_chunk(p, ep, spec, ",") { - struct port_range xrange; - - if (isdigit(*p)) { - /* Include range, parse later */ - exclude_only = false; - continue; - } - - if (parse_keyword(p, &p, "auto") == 0) { - if (p != ep) /* Garbage after the keyword */ - goto bad; - - if (!(fwd->caps & FWD_CAP_SCAN)) { - die( -"'auto' port forwarding is only allowed for pasta"); - } - - flags |= FWD_SCAN; - continue; - } - - /* Should be an exclude range */ - if (*p != '~') - goto bad; - p++; - - if (parse_port_range(p, &p, &xrange)) - goto bad; - if (p != ep) /* Garbage after the range */ - goto bad; - - for (i = xrange.first; i <= xrange.last; i++) - bitmap_set(exclude, i); - } - - if (exclude_only) { - /* Exclude ephemeral ports */ - fwd_port_map_ephemeral(exclude); - - conf_ports_range_except(fwd, proto, addr, ifname, - 1, NUM_PORTS - 1, exclude, - 1, flags | FWD_WEAK); - return; - } - - /* Now process base ranges, skipping exclusions */ - for_each_chunk(p, ep, spec, ",") { - struct port_range orig_range, mapped_range; - - if (!isdigit(*p)) - /* Already parsed */ - continue; - - if (parse_port_range(p, &p, &orig_range)) - goto bad; - - if (*p == ':') { /* There's a range to map to as well */ - if (parse_port_range(p + 1, &p, &mapped_range)) - goto bad; - if ((mapped_range.last - mapped_range.first) != - (orig_range.last - orig_range.first)) - goto bad; - } else { - mapped_range = orig_range; - } - - if (p != ep) /* Garbage after the ranges */ - goto bad; - - conf_ports_range_except(fwd, proto, addr, ifname, - orig_range.first, orig_range.last, - exclude, - mapped_range.first, flags); - } - - return; -bad: - die("Invalid port specifier '%s'", spec); -} - -/** - * conf_ports() - Parse port configuration options, initialise UDP/TCP sockets - * @optname: Short option name, t, T, u, or U - * @optarg: Option argument (port specification) - * @fwd: Forwarding table to be updated - */ -static void conf_ports(char optname, const char *optarg, struct fwd_table *fwd) -{ - union inany_addr addr_buf = inany_any6, *addr = &addr_buf; - char buf[BUFSIZ], *spec, *ifname = NULL; - uint8_t proto; - - if (optname == 't' || optname == 'T') - proto = IPPROTO_TCP; - else if (optname == 'u' || optname == 'U') - proto = IPPROTO_UDP; - else - assert(0); - - if (!strcmp(optarg, "none")) { - unsigned i; - - for (i = 0; i < fwd->count; i++) { - if (fwd->rules[i].proto == proto) { - die("-%c none conflicts with previous options", - optname); - } - } - return; - } - - strncpy(buf, optarg, sizeof(buf) - 1); - - if ((spec = strchr(buf, '/'))) { - *spec = 0; - spec++; - - if (optname != 't' && optname != 'u') - die("Listening address not allowed for -%c %s", - optname, optarg); - - if ((ifname = strchr(buf, '%'))) { - *ifname = 0; - ifname++; - - /* spec is already advanced one past the '/', - * so the length of the given ifname is: - * (spec - ifname - 1) - */ - if (spec - ifname - 1 >= IFNAMSIZ) { - die("Interface name '%s' is too long (max %u)", - ifname, IFNAMSIZ - 1); - } - } - - if (ifname == buf + 1) { /* Interface without address */ - addr = NULL; - } else { - char *p = buf; - - /* Allow square brackets for IPv4 too for convenience */ - if (*p == '[' && p[strlen(p) - 1] == ']') { - p[strlen(p) - 1] = '\0'; - p++; - } - - if (!inany_pton(p, addr)) - die("Bad forwarding address '%s'", p); - } - } else { - spec = buf; - - addr = NULL; - } - - if (optname == 'T' || optname == 'U') { - assert(!addr && !ifname); - - if (!(fwd->caps & FWD_CAP_IFNAME)) { - warn( -"SO_BINDTODEVICE unavailable, forwarding only 127.0.0.1 and ::1 for '-%c %s'", - optname, optarg); - - if (fwd->caps & FWD_CAP_IPV4) { - conf_ports_spec(fwd, proto, - &inany_loopback4, NULL, spec); - } - if (fwd->caps & FWD_CAP_IPV6) { - conf_ports_spec(fwd, proto, - &inany_loopback6, NULL, spec); - } - return; - } - - ifname = "lo"; - } - - if (ifname && !(fwd->caps & FWD_CAP_IFNAME)) { - die( -"Device binding for '-%c %s' unsupported (requires kernel 5.7+)", - optname, optarg); - } - - conf_ports_spec(fwd, proto, addr, ifname, spec); -} - /** * add_dns4() - Possibly add the IPv4 address of a DNS resolver to configuration * @c: Execution context @@ -2160,16 +1800,16 @@ void conf(struct ctx *c, int argc, char **argv) if (name == 't') { opt_t = true; - conf_ports(name, optarg, c->fwd[PIF_HOST]); + fwd_rule_parse(name, optarg, c->fwd[PIF_HOST]); } else if (name == 'u') { opt_u = true; - conf_ports(name, optarg, c->fwd[PIF_HOST]); + fwd_rule_parse(name, optarg, c->fwd[PIF_HOST]); } else if (name == 'T') { opt_T = true; - conf_ports(name, optarg, c->fwd[PIF_SPLICE]); + fwd_rule_parse(name, optarg, c->fwd[PIF_SPLICE]); } else if (name == 'U') { opt_U = true; - conf_ports(name, optarg, c->fwd[PIF_SPLICE]); + fwd_rule_parse(name, optarg, c->fwd[PIF_SPLICE]); } } while (name != -1); @@ -2221,13 +1861,13 @@ void conf(struct ctx *c, int argc, char **argv) if (c->mode == MODE_PASTA) { if (!opt_t) - conf_ports('t', "auto", c->fwd[PIF_HOST]); + fwd_rule_parse('t', "auto", c->fwd[PIF_HOST]); if (!opt_T) - conf_ports('T', "auto", c->fwd[PIF_SPLICE]); + fwd_rule_parse('T', "auto", c->fwd[PIF_SPLICE]); if (!opt_u) - conf_ports('u', "auto", c->fwd[PIF_HOST]); + fwd_rule_parse('u', "auto", c->fwd[PIF_HOST]); if (!opt_U) - conf_ports('U', "auto", c->fwd[PIF_SPLICE]); + fwd_rule_parse('U', "auto", c->fwd[PIF_SPLICE]); } if (!c->quiet) diff --git a/fwd.c b/fwd.c index a6d75b74..728a783c 100644 --- a/fwd.c +++ b/fwd.c @@ -275,100 +275,6 @@ void fwd_rule_init(struct ctx *c) c->fwd[PIF_SPLICE] = &fwd_out; } -/** - * fwd_rule_add() - Validate and add a rule to a forwarding table - * @fwd: Table to add to - * @new: Rule to add - * - * Return: 0 on success, negative error code on failure - */ -int fwd_rule_add(struct fwd_table *fwd, const struct fwd_rule *new) -{ - /* Flags which can be set from the caller */ - const uint8_t allowed_flags = FWD_WEAK | FWD_SCAN | FWD_DUAL_STACK_ANY; - unsigned num = (unsigned)new->last - new->first + 1; - unsigned port; - - if (new->first > new->last) { - warn("Rule has invalid port range %u-%u", - new->first, new->last); - return -EINVAL; - } - if (!new->first) { - warn("Forwarding rule attempts to map from port 0"); - return -EINVAL; - } - if (!new->to || - (in_port_t)(new->to + new->last - new->first) < new->to) { - warn("Forwarding rule attempts to map to port 0"); - return -EINVAL; - } - if (new->flags & ~allowed_flags) { - warn("Rule has invalid flags 0x%hhx", - new->flags & ~allowed_flags); - return -EINVAL; - } - if (new->flags & FWD_DUAL_STACK_ANY) { - if (!inany_equals(&new->addr, &inany_any6)) { - char astr[INANY_ADDRSTRLEN]; - - warn("Dual stack rule has non-wildcard address %s", - inany_ntop(&new->addr, astr, sizeof(astr))); - return -EINVAL; - } - if (!(fwd->caps & FWD_CAP_IPV4)) { - warn("Dual stack forward, but IPv4 not enabled"); - return -EINVAL; - } - if (!(fwd->caps & FWD_CAP_IPV6)) { - warn("Dual stack forward, but IPv6 not enabled"); - return -EINVAL; - } - } else { - if (inany_v4(&new->addr) && !(fwd->caps & FWD_CAP_IPV4)) { - warn("IPv4 forward, but IPv4 not enabled"); - return -EINVAL; - } - if (!inany_v4(&new->addr) && !(fwd->caps & FWD_CAP_IPV6)) { - warn("IPv6 forward, but IPv6 not enabled"); - return -EINVAL; - } - } - if (new->proto == IPPROTO_TCP) { - if (!(fwd->caps & FWD_CAP_TCP)) { - warn("Can't add TCP forwarding rule, TCP not enabled"); - return -EINVAL; - } - } else if (new->proto == IPPROTO_UDP) { - if (!(fwd->caps & FWD_CAP_UDP)) { - warn("Can't add UDP forwarding rule, UDP not enabled"); - return -EINVAL; - } - } else { - warn("Unsupported protocol 0x%hhx (%s) for forwarding rule", - new->proto, ipproto_name(new->proto)); - return -EINVAL; - } - - if (fwd->count >= ARRAY_SIZE(fwd->rules)) { - warn("Too many rules (maximum %u)", ARRAY_SIZE(fwd->rules)); - return -ENOSPC; - } - if ((fwd->sock_count + num) > ARRAY_SIZE(fwd->socks)) { - warn("Rules require too many listening sockets (maximum %u)", - ARRAY_SIZE(fwd->socks)); - return -ENOSPC; - } - - fwd->rulesocks[fwd->count] = &fwd->socks[fwd->sock_count]; - for (port = new->first; port <= new->last; port++) - fwd->rulesocks[fwd->count][port - new->first] = -1; - - fwd->rules[fwd->count++] = *new; - fwd->sock_count += num; - return 0; -} - /** * fwd_rule_match() - Does a prospective flow match a given forwarding rule? * @rule: Forwarding rule diff --git a/fwd.h b/fwd.h index e664d1d0..8f845d09 100644 --- a/fwd.h +++ b/fwd.h @@ -20,8 +20,6 @@ struct flowside; -#define FWD_RULE_BITS 8 -#define MAX_FWD_RULES MAX_FROM_BITS(FWD_RULE_BITS) #define FWD_NO_HINT (-1) /** @@ -36,36 +34,6 @@ struct fwd_listen_ref { unsigned rule :FWD_RULE_BITS; }; -/* Maximum number of listening sockets (per pif) - * - * Rationale: This lets us listen on every port for two addresses and two - * protocols (which we need for -T auto -U auto without SO_BINDTODEVICE), plus a - * comfortable number of extras. - */ -#define MAX_LISTEN_SOCKS (NUM_PORTS * 5) - -/** - * struct fwd_table - Forwarding state (per initiating pif) - * @caps: Forwarding capabilities for this initiating pif - * @count: Number of forwarding rules - * @rules: Array of forwarding rules - * @rulesocks: Parallel array of @rules (@count valid entries) of pointers to - * @socks entries giving the start of the corresponding rule's - * sockets within the larger array - * @sock_count: Number of entries used in @socks (for all rules combined) - * @socks: Listening sockets for forwarding - */ -struct fwd_table { - uint32_t caps; - unsigned count; - struct fwd_rule rules[MAX_FWD_RULES]; - int *rulesocks[MAX_FWD_RULES]; - unsigned sock_count; - int socks[MAX_LISTEN_SOCKS]; -}; - -#define PORT_BITMAP_SIZE DIV_ROUND_UP(NUM_PORTS, 8) - /** * struct fwd_scan - Port scanning state for a protocol+direction * @scan4: /proc/net fd to scan for IPv4 ports when in AUTO mode @@ -81,7 +49,6 @@ struct fwd_scan { #define FWD_PORT_SCAN_INTERVAL 1000 /* ms */ void fwd_rule_init(struct ctx *c); -int fwd_rule_add(struct fwd_table *fwd, const struct fwd_rule *new); const struct fwd_rule *fwd_rule_search(const struct fwd_table *fwd, const struct flowside *ini, uint8_t proto, int hint); diff --git a/fwd_rule.c b/fwd_rule.c index 9d489827..cd3dec04 100644 --- a/fwd_rule.c +++ b/fwd_rule.c @@ -15,6 +15,7 @@ * Author: David Gibson <david(a)gibson.dropbear.id.au> */ +#include <ctype.h> #include <errno.h> #include <fcntl.h> #include <stdio.h> @@ -89,7 +90,7 @@ parse_err: * fwd_port_map_ephemeral() - Mark ephemeral ports in a bitmap * @map: Bitmap to update */ -void fwd_port_map_ephemeral(uint8_t *map) +static void fwd_port_map_ephemeral(uint8_t *map) { unsigned port; @@ -123,6 +124,7 @@ const union inany_addr *fwd_rule_addr(const struct fwd_rule *rule) */ __attribute__((noinline)) #endif +/* cppcheck-suppress staticFunction */ const char *fwd_rule_fmt(const struct fwd_rule *rule, char *dst, size_t size) { const char *percent = *rule->ifname ? "%" : ""; @@ -199,8 +201,8 @@ static bool fwd_rule_conflicts(const struct fwd_rule *a, const struct fwd_rule * * @rules: Existing rules against which to test * @count: Number of rules in @rules */ -void fwd_rule_conflict_check(const struct fwd_rule *new, - const struct fwd_rule *rules, size_t count) +static void fwd_rule_conflict_check(const struct fwd_rule *new, + const struct fwd_rule *rules, size_t count) { unsigned i; @@ -215,3 +217,459 @@ void fwd_rule_conflict_check(const struct fwd_rule *new, fwd_rule_fmt(&rules[i], rulestr, sizeof(rulestr))); } } + +/** + * fwd_rule_add() - Validate and add a rule to a forwarding table + * @fwd: Table to add to + * @new: Rule to add + * + * Return: 0 on success, negative error code on failure + */ +static int fwd_rule_add(struct fwd_table *fwd, const struct fwd_rule *new) +{ + /* Flags which can be set from the caller */ + const uint8_t allowed_flags = FWD_WEAK | FWD_SCAN | FWD_DUAL_STACK_ANY; + unsigned num = (unsigned)new->last - new->first + 1; + unsigned port; + + if (new->first > new->last) { + warn("Rule has invalid port range %u-%u", + new->first, new->last); + return -EINVAL; + } + if (!new->first) { + warn("Forwarding rule attempts to map from port 0"); + return -EINVAL; + } + if (!new->to || + (in_port_t)(new->to + new->last - new->first) < new->to) { + warn("Forwarding rule attempts to map to port 0"); + return -EINVAL; + } + if (new->flags & ~allowed_flags) { + warn("Rule has invalid flags 0x%hhx", + new->flags & ~allowed_flags); + return -EINVAL; + } + if (new->flags & FWD_DUAL_STACK_ANY) { + if (!inany_equals(&new->addr, &inany_any6)) { + char astr[INANY_ADDRSTRLEN]; + + warn("Dual stack rule has non-wildcard address %s", + inany_ntop(&new->addr, astr, sizeof(astr))); + return -EINVAL; + } + if (!(fwd->caps & FWD_CAP_IPV4)) { + warn("Dual stack forward, but IPv4 not enabled"); + return -EINVAL; + } + if (!(fwd->caps & FWD_CAP_IPV6)) { + warn("Dual stack forward, but IPv6 not enabled"); + return -EINVAL; + } + } else { + if (inany_v4(&new->addr) && !(fwd->caps & FWD_CAP_IPV4)) { + warn("IPv4 forward, but IPv4 not enabled"); + return -EINVAL; + } + if (!inany_v4(&new->addr) && !(fwd->caps & FWD_CAP_IPV6)) { + warn("IPv6 forward, but IPv6 not enabled"); + return -EINVAL; + } + } + if (new->proto == IPPROTO_TCP) { + if (!(fwd->caps & FWD_CAP_TCP)) { + warn("Can't add TCP forwarding rule, TCP not enabled"); + return -EINVAL; + } + } else if (new->proto == IPPROTO_UDP) { + if (!(fwd->caps & FWD_CAP_UDP)) { + warn("Can't add UDP forwarding rule, UDP not enabled"); + return -EINVAL; + } + } else { + warn("Unsupported protocol 0x%hhx (%s) for forwarding rule", + new->proto, ipproto_name(new->proto)); + return -EINVAL; + } + + if (fwd->count >= ARRAY_SIZE(fwd->rules)) { + warn("Too many rules (maximum %u)", ARRAY_SIZE(fwd->rules)); + return -ENOSPC; + } + if ((fwd->sock_count + num) > ARRAY_SIZE(fwd->socks)) { + warn("Rules require too many listening sockets (maximum %u)", + ARRAY_SIZE(fwd->socks)); + return -ENOSPC; + } + + fwd->rulesocks[fwd->count] = &fwd->socks[fwd->sock_count]; + for (port = new->first; port <= new->last; port++) + fwd->rulesocks[fwd->count][port - new->first] = -1; + + fwd->rules[fwd->count++] = *new; + fwd->sock_count += num; + return 0; +} + +/** + * port_range() - Represents a non-empty range of ports + * @first: First port number in the range + * @last: Last port number in the range (inclusive) + * + * Invariant: @last >= @first + */ +struct port_range { + in_port_t first, last; +}; + +/** + * parse_port_range() - Parse a range of port numbers '<first>[-<last>]' + * @s: String to parse + * @endptr: Update to the character after the parsed range (similar to + * strtol() etc.) + * @range: Update with the parsed values on success + * + * Return: -EINVAL on parsing error, -ERANGE on out of range port + * numbers, 0 on success + */ +static int parse_port_range(const char *s, const char **endptr, + struct port_range *range) +{ + unsigned long first, last; + char *ep; + + last = first = strtoul(s, &ep, 10); + if (ep == s) /* Parsed nothing */ + return -EINVAL; + if (*ep == '-') { /* we have a last value too */ + const char *lasts = ep + 1; + last = strtoul(lasts, &ep, 10); + if (ep == lasts) /* Parsed nothing */ + return -EINVAL; + } + + if ((last < first) || (last >= NUM_PORTS)) + return -ERANGE; + + range->first = first; + range->last = last; + *endptr = ep; + + return 0; +} + +/** + * parse_keyword() - Parse a literal keyword + * @s: String to parse + * @endptr: Update to the character after the keyword + * @kw: Keyword to accept + * + * Return: 0, if @s starts with @kw, -EINVAL if it does not + */ +static int parse_keyword(const char *s, const char **endptr, const char *kw) +{ + size_t len = strlen(kw); + + if (strlen(s) < len) + return -EINVAL; + + if (memcmp(s, kw, len)) + return -EINVAL; + + *endptr = s + len; + return 0; +} + +/** + * fwd_rule_range_except() - Set up forwarding for a range of ports minus a + * bitmap of exclusions + * @fwd: Forwarding table to be updated + * @proto: Protocol to forward + * @addr: Listening address + * @ifname: Listening interface + * @first: First port to forward + * @last: Last port to forward + * @exclude: Bitmap of ports to exclude (may be NULL) + * @to: Port to translate @first to when forwarding + * @flags: Flags for forwarding entries + */ +static void fwd_rule_range_except(struct fwd_table *fwd, uint8_t proto, + const union inany_addr *addr, + const char *ifname, + uint16_t first, uint16_t last, + const uint8_t *exclude, uint16_t to, + uint8_t flags) +{ + struct fwd_rule rule = { + .addr = addr ? *addr : inany_any6, + .ifname = { 0 }, + .proto = proto, + .flags = flags, + }; + char rulestr[FWD_RULE_STRLEN]; + unsigned delta = to - first; + unsigned base, i; + + if (!addr) + rule.flags |= FWD_DUAL_STACK_ANY; + if (ifname) { + int ret; + + ret = snprintf(rule.ifname, sizeof(rule.ifname), + "%s", ifname); + if (ret <= 0 || (size_t)ret >= sizeof(rule.ifname)) + die("Invalid interface name: %s", ifname); + } + + for (base = first; base <= last; base++) { + if (exclude && bitmap_isset(exclude, base)) + continue; + + for (i = base; i <= last; i++) { + if (exclude && bitmap_isset(exclude, i)) + break; + } + + rule.first = base; + rule.last = i - 1; + rule.to = base + delta; + + fwd_rule_conflict_check(&rule, fwd->rules, fwd->count); + if (fwd_rule_add(fwd, &rule) < 0) + goto fail; + + base = i - 1; + } + return; + +fail: + die("Unable to add rule %s", + fwd_rule_fmt(&rule, rulestr, sizeof(rulestr))); +} + +/* + * for_each_chunk - Step through delimited chunks of a string + * @p_: Pointer to start of each chunk (updated) + * @ep_: Pointer to end of each chunk (updated) + * @s_: String to step through + * @sep_: String of all allowed delimiters + */ +#define for_each_chunk(p_, ep_, s_, sep_) \ + for ((p_) = (s_); \ + (ep_) = (p_) + strcspn((p_), (sep_)), *(p_); \ + (p_) = *(ep_) ? (ep_) + 1 : (ep_)) + +/** + * fwd_rule_parse_ports() - Parse port range(s) specifier + * @fwd: Forwarding table to be updated + * @proto: Protocol to forward + * @addr: Listening address for forwarding + * @ifname: Interface name for listening + * @spec: Port range(s) specifier + */ +static void fwd_rule_parse_ports(struct fwd_table *fwd, uint8_t proto, + const union inany_addr *addr, + const char *ifname, + const char *spec) +{ + uint8_t exclude[PORT_BITMAP_SIZE] = { 0 }; + bool exclude_only = true; + const char *p, *ep; + uint8_t flags = 0; + unsigned i; + + if (!strcmp(spec, "all")) { + /* Treat "all" as equivalent to "": all non-ephemeral ports */ + spec = ""; + } + + /* Parse excluded ranges and "auto" in the first pass */ + for_each_chunk(p, ep, spec, ",") { + struct port_range xrange; + + if (isdigit(*p)) { + /* Include range, parse later */ + exclude_only = false; + continue; + } + + if (parse_keyword(p, &p, "auto") == 0) { + if (p != ep) /* Garbage after the keyword */ + goto bad; + + if (!(fwd->caps & FWD_CAP_SCAN)) { + die( +"'auto' port forwarding is only allowed for pasta"); + } + + flags |= FWD_SCAN; + continue; + } + + /* Should be an exclude range */ + if (*p != '~') + goto bad; + p++; + + if (parse_port_range(p, &p, &xrange)) + goto bad; + if (p != ep) /* Garbage after the range */ + goto bad; + + for (i = xrange.first; i <= xrange.last; i++) + bitmap_set(exclude, i); + } + + if (exclude_only) { + /* Exclude ephemeral ports */ + fwd_port_map_ephemeral(exclude); + + fwd_rule_range_except(fwd, proto, addr, ifname, + 1, NUM_PORTS - 1, exclude, + 1, flags | FWD_WEAK); + return; + } + + /* Now process base ranges, skipping exclusions */ + for_each_chunk(p, ep, spec, ",") { + struct port_range orig_range, mapped_range; + + if (!isdigit(*p)) + /* Already parsed */ + continue; + + if (parse_port_range(p, &p, &orig_range)) + goto bad; + + if (*p == ':') { /* There's a range to map to as well */ + if (parse_port_range(p + 1, &p, &mapped_range)) + goto bad; + if ((mapped_range.last - mapped_range.first) != + (orig_range.last - orig_range.first)) + goto bad; + } else { + mapped_range = orig_range; + } + + if (p != ep) /* Garbage after the ranges */ + goto bad; + + fwd_rule_range_except(fwd, proto, addr, ifname, + orig_range.first, orig_range.last, + exclude, + mapped_range.first, flags); + } + + return; +bad: + die("Invalid port specifier '%s'", spec); +} + +/** + * fwd_rule_parse() - Parse port configuration option + * @optname: Short option name, t, T, u, or U + * @optarg: Option argument (port specification) + * @fwd: Forwarding table to be updated + */ +void fwd_rule_parse(char optname, const char *optarg, struct fwd_table *fwd) +{ + union inany_addr addr_buf = inany_any6, *addr = &addr_buf; + char buf[BUFSIZ], *spec, *ifname = NULL; + uint8_t proto; + + if (optname == 't' || optname == 'T') + proto = IPPROTO_TCP; + else if (optname == 'u' || optname == 'U') + proto = IPPROTO_UDP; + else + assert(0); + + if (!strcmp(optarg, "none")) { + unsigned i; + + for (i = 0; i < fwd->count; i++) { + if (fwd->rules[i].proto == proto) { + die("-%c none conflicts with previous options", + optname); + } + } + return; + } + + strncpy(buf, optarg, sizeof(buf) - 1); + + if ((spec = strchr(buf, '/'))) { + *spec = 0; + spec++; + + if (optname != 't' && optname != 'u') + die("Listening address not allowed for -%c %s", + optname, optarg); + + if ((ifname = strchr(buf, '%'))) { + *ifname = 0; + ifname++; + + /* spec is already advanced one past the '/', + * so the length of the given ifname is: + * (spec - ifname - 1) + */ + if (spec - ifname - 1 >= IFNAMSIZ) { + die("Interface name '%s' is too long (max %u)", + ifname, IFNAMSIZ - 1); + } + } + + if (ifname == buf + 1) { /* Interface without address */ + addr = NULL; + } else { + char *p = buf; + + /* Allow square brackets for IPv4 too for convenience */ + if (*p == '[' && p[strlen(p) - 1] == ']') { + p[strlen(p) - 1] = '\0'; + p++; + } + + if (!inany_pton(p, addr)) + die("Bad forwarding address '%s'", p); + } + } else { + spec = buf; + + addr = NULL; + } + + if (optname == 'T' || optname == 'U') { + assert(!addr && !ifname); + + if (!(fwd->caps & FWD_CAP_IFNAME)) { + warn( +"SO_BINDTODEVICE unavailable, forwarding only 127.0.0.1 and ::1 for '-%c %s'", + optname, optarg); + + if (fwd->caps & FWD_CAP_IPV4) { + fwd_rule_parse_ports(fwd, proto, + &inany_loopback4, NULL, + spec); + } + if (fwd->caps & FWD_CAP_IPV6) { + fwd_rule_parse_ports(fwd, proto, + &inany_loopback6, NULL, + spec); + } + return; + } + + ifname = "lo"; + } + + if (ifname && !(fwd->caps & FWD_CAP_IFNAME)) { + die( +"Device binding for '-%c %s' unsupported (requires kernel 5.7+)", + optname, optarg); + } + + fwd_rule_parse_ports(fwd, proto, addr, ifname, spec); +} diff --git a/fwd_rule.h b/fwd_rule.h index 5c7b67aa..f0f4efda 100644 --- a/fwd_rule.h +++ b/fwd_rule.h @@ -19,6 +19,7 @@ /* Number of ports for both TCP and UDP */ #define NUM_PORTS (1U << 16) +#define PORT_BITMAP_SIZE DIV_ROUND_UP(NUM_PORTS, 8) /* Forwarding capability bits */ #define FWD_CAP_IPV4 BIT(0) @@ -54,8 +55,38 @@ struct fwd_rule { uint8_t flags; }; +#define FWD_RULE_BITS 8 +#define MAX_FWD_RULES MAX_FROM_BITS(FWD_RULE_BITS) + +/* Maximum number of listening sockets (per pif) + * + * Rationale: This lets us listen on every port for two addresses and two + * protocols (which we need for -T auto -U auto without SO_BINDTODEVICE), plus a + * comfortable number of extras. + */ +#define MAX_LISTEN_SOCKS (NUM_PORTS * 5) + +/** + * struct fwd_table - Forwarding state (per initiating pif) + * @caps: Forwarding capabilities for this initiating pif + * @count: Number of forwarding rules + * @rules: Array of forwarding rules + * @rulesocks: Parallel array of @rules (@count valid entries) of pointers to + * @socks entries giving the start of the corresponding rule's + * sockets within the larger array + * @sock_count: Number of entries used in @socks (for all rules combined) + * @socks: Listening sockets for forwarding + */ +struct fwd_table { + uint32_t caps; + unsigned count; + struct fwd_rule rules[MAX_FWD_RULES]; + int *rulesocks[MAX_FWD_RULES]; + unsigned sock_count; + int socks[MAX_LISTEN_SOCKS]; +}; + void fwd_probe_ephemeral(void); -void fwd_port_map_ephemeral(uint8_t *map); #define FWD_RULE_STRLEN \ (IPPROTO_STRLEN - 1 \ @@ -67,7 +98,6 @@ void fwd_port_map_ephemeral(uint8_t *map); const union inany_addr *fwd_rule_addr(const struct fwd_rule *rule); const char *fwd_rule_fmt(const struct fwd_rule *rule, char *dst, size_t size); void fwd_rules_info(const struct fwd_rule *rules, size_t count); -void fwd_rule_conflict_check(const struct fwd_rule *new, - const struct fwd_rule *rules, size_t count); +void fwd_rule_parse(char optname, const char *optarg, struct fwd_table *fwd); #endif /* FWD_RULE_H */ -- 2.53.0

1 0

[PATCH v5 02/18] fwd_rule: Move ephemeral port probing to fwd_rule.c
by David Gibson 21 Apr '26

21 Apr '26

We want to move parsing of forward rule options to fwd_rule.c so it can eventually be shared with a configuration client. As a preliminary step, move the ephemeral port probing there, which that will need to use. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> Reviewed-by: Laurent Vivier <lvivier(a)redhat.com> --- fwd.c | 73 -------------------------------------------------- fwd.h | 6 ----- fwd_rule.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ fwd_rule.h | 6 +++++ 4 files changed, 84 insertions(+), 79 deletions(-) diff --git a/fwd.c b/fwd.c index 979c1494..a6d75b74 100644 --- a/fwd.c +++ b/fwd.c @@ -34,12 +34,6 @@ #include "arp.h" #include "ndp.h" -/* Ephemeral port range: values from RFC 6335 */ -static in_port_t fwd_ephemeral_min = (1 << 15) + (1 << 14); -static in_port_t fwd_ephemeral_max = NUM_PORTS - 1; - -#define PORT_RANGE_SYSCTL "/proc/sys/net/ipv4/ip_local_port_range" - #define NEIGH_TABLE_SLOTS 1024 #define NEIGH_TABLE_SIZE (NEIGH_TABLE_SLOTS / 2) static_assert((NEIGH_TABLE_SLOTS & (NEIGH_TABLE_SLOTS - 1)) == 0, @@ -249,73 +243,6 @@ void fwd_neigh_table_init(const struct ctx *c) fwd_neigh_table_update(c, &mga, c->our_tap_mac, true); } -/** fwd_probe_ephemeral() - Determine what ports this host considers ephemeral - * - * Work out what ports the host thinks are emphemeral and record it for later - * use by fwd_port_is_ephemeral(). If we're unable to probe, assume the range - * recommended by RFC 6335. - */ -void fwd_probe_ephemeral(void) -{ - char *line, *tab, *end; - struct lineread lr; - long min, max; - ssize_t len; - int fd; - - fd = open(PORT_RANGE_SYSCTL, O_RDONLY | O_CLOEXEC); - if (fd < 0) { - warn_perror("Unable to open %s", PORT_RANGE_SYSCTL); - return; - } - - lineread_init(&lr, fd); - len = lineread_get(&lr, &line); - close(fd); - - if (len < 0) - goto parse_err; - - tab = strchr(line, '\t'); - if (!tab) - goto parse_err; - *tab = '\0'; - - errno = 0; - min = strtol(line, &end, 10); - if (*end || errno) - goto parse_err; - - errno = 0; - max = strtol(tab + 1, &end, 10); - if (*end || errno) - goto parse_err; - - if (min < 0 || min >= (long)NUM_PORTS || - max < 0 || max >= (long)NUM_PORTS) - goto parse_err; - - fwd_ephemeral_min = min; - fwd_ephemeral_max = max; - - return; - -parse_err: - warn("Unable to parse %s", PORT_RANGE_SYSCTL); -} - -/** - * fwd_port_map_ephemeral() - Mark ephemeral ports in a bitmap - * @map: Bitmap to update - */ -void fwd_port_map_ephemeral(uint8_t *map) -{ - unsigned port; - - for (port = fwd_ephemeral_min; port <= fwd_ephemeral_max; port++) - bitmap_set(map, port); -} - /* Forwarding table storage, generally accessed via pointers in struct ctx */ static struct fwd_table fwd_in; static struct fwd_table fwd_out; diff --git a/fwd.h b/fwd.h index 3e365d35..e664d1d0 100644 --- a/fwd.h +++ b/fwd.h @@ -20,12 +20,6 @@ struct flowside; -/* Number of ports for both TCP and UDP */ -#define NUM_PORTS (1U << 16) - -void fwd_probe_ephemeral(void); -void fwd_port_map_ephemeral(uint8_t *map); - #define FWD_RULE_BITS 8 #define MAX_FWD_RULES MAX_FROM_BITS(FWD_RULE_BITS) #define FWD_NO_HINT (-1) diff --git a/fwd_rule.c b/fwd_rule.c index 47d8df1c..9d489827 100644 --- a/fwd_rule.c +++ b/fwd_rule.c @@ -15,9 +15,87 @@ * Author: David Gibson <david(a)gibson.dropbear.id.au> */ +#include <errno.h> +#include <fcntl.h> #include <stdio.h> +#include <unistd.h> #include "fwd_rule.h" +#include "lineread.h" +#include "log.h" + +/* Ephemeral port range: values from RFC 6335 */ +static in_port_t fwd_ephemeral_min = (1 << 15) + (1 << 14); +static in_port_t fwd_ephemeral_max = NUM_PORTS - 1; + +#define PORT_RANGE_SYSCTL "/proc/sys/net/ipv4/ip_local_port_range" + +/** fwd_probe_ephemeral() - Determine what ports this host considers ephemeral + * + * Work out what ports the host thinks are emphemeral and record it for later + * use by fwd_port_is_ephemeral(). If we're unable to probe, assume the range + * recommended by RFC 6335. + */ +void fwd_probe_ephemeral(void) +{ + char *line, *tab, *end; + struct lineread lr; + long min, max; + ssize_t len; + int fd; + + fd = open(PORT_RANGE_SYSCTL, O_RDONLY | O_CLOEXEC); + if (fd < 0) { + warn_perror("Unable to open %s", PORT_RANGE_SYSCTL); + return; + } + + lineread_init(&lr, fd); + len = lineread_get(&lr, &line); + close(fd); + + if (len < 0) + goto parse_err; + + tab = strchr(line, '\t'); + if (!tab) + goto parse_err; + *tab = '\0'; + + errno = 0; + min = strtol(line, &end, 10); + if (*end || errno) + goto parse_err; + + errno = 0; + max = strtol(tab + 1, &end, 10); + if (*end || errno) + goto parse_err; + + if (min < 0 || min >= (long)NUM_PORTS || + max < 0 || max >= (long)NUM_PORTS) + goto parse_err; + + fwd_ephemeral_min = min; + fwd_ephemeral_max = max; + + return; + +parse_err: + warn("Unable to parse %s", PORT_RANGE_SYSCTL); +} + +/** + * fwd_port_map_ephemeral() - Mark ephemeral ports in a bitmap + * @map: Bitmap to update + */ +void fwd_port_map_ephemeral(uint8_t *map) +{ + unsigned port; + + for (port = fwd_ephemeral_min; port <= fwd_ephemeral_max; port++) + bitmap_set(map, port); +} /** * fwd_rule_addr() - Return match address for a rule diff --git a/fwd_rule.h b/fwd_rule.h index edba6782..5c7b67aa 100644 --- a/fwd_rule.h +++ b/fwd_rule.h @@ -17,6 +17,9 @@ #include "inany.h" #include "bitmap.h" +/* Number of ports for both TCP and UDP */ +#define NUM_PORTS (1U << 16) + /* Forwarding capability bits */ #define FWD_CAP_IPV4 BIT(0) #define FWD_CAP_IPV6 BIT(1) @@ -51,6 +54,9 @@ struct fwd_rule { uint8_t flags; }; +void fwd_probe_ephemeral(void); +void fwd_port_map_ephemeral(uint8_t *map); + #define FWD_RULE_STRLEN \ (IPPROTO_STRLEN - 1 \ + INANY_ADDRSTRLEN - 1 \ -- 2.53.0

1 0

[PATCH v5 01/18] conf, fwd: Stricter rule checking in fwd_rule_add()
by David Gibson 21 Apr '26

21 Apr '26

Although fwd_rule_add() performs some sanity checks on the rule it is given, there are invalid rules we don't check for, assuming that its callers will do that. That won't be enough when we can get rules inserted by a dynamic update client without going through the existing parsing code. So, add stricter checks to fwd_rule_add(), which is now possible thanks to the capabilities bits in the struct fwd_table. Where those duplicate existing checks in the callers, remove the old copies. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- conf.c | 21 --------------------- fwd.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++----- 2 files changed, 47 insertions(+), 26 deletions(-) diff --git a/conf.c b/conf.c index 6e884e54..b470b0d8 100644 --- a/conf.c +++ b/conf.c @@ -176,8 +176,6 @@ static void conf_ports_range_except(struct fwd_table *fwd, uint8_t proto, die("Invalid interface name: %s", ifname); } - assert(first != 0); - for (base = first; base <= last; base++) { if (exclude && bitmap_isset(exclude, base)) continue; @@ -310,10 +308,6 @@ static void conf_ports_spec(struct fwd_table *fwd, uint8_t proto, if (p != ep) /* Garbage after the ranges */ goto bad; - if (orig_range.first == 0) { - die("Can't forward port 0 included in '%s'", spec); - } - conf_ports_range_except(fwd, proto, addr, ifname, orig_range.first, orig_range.last, exclude, @@ -356,11 +350,6 @@ static void conf_ports(char optname, const char *optarg, struct fwd_table *fwd) return; } - if (proto == IPPROTO_TCP && !(fwd->caps & FWD_CAP_TCP)) - die("TCP port forwarding requested but TCP is disabled"); - if (proto == IPPROTO_UDP && !(fwd->caps & FWD_CAP_UDP)) - die("UDP port forwarding requested but UDP is disabled"); - strncpy(buf, optarg, sizeof(buf) - 1); if ((spec = strchr(buf, '/'))) { @@ -405,16 +394,6 @@ static void conf_ports(char optname, const char *optarg, struct fwd_table *fwd) addr = NULL; } - if (addr) { - if (!(fwd->caps & FWD_CAP_IPV4) && inany_v4(addr)) { - die("IPv4 is disabled, can't use -%c %s", - optname, optarg); - } else if (!(fwd->caps & FWD_CAP_IPV6) && !inany_v4(addr)) { - die("IPv6 is disabled, can't use -%c %s", - optname, optarg); - } - } - if (optname == 'T' || optname == 'U') { assert(!addr && !ifname); diff --git a/fwd.c b/fwd.c index c7fd1a9d..979c1494 100644 --- a/fwd.c +++ b/fwd.c @@ -367,17 +367,59 @@ int fwd_rule_add(struct fwd_table *fwd, const struct fwd_rule *new) new->first, new->last); return -EINVAL; } + if (!new->first) { + warn("Forwarding rule attempts to map from port 0"); + return -EINVAL; + } + if (!new->to || + (in_port_t)(new->to + new->last - new->first) < new->to) { + warn("Forwarding rule attempts to map to port 0"); + return -EINVAL; + } if (new->flags & ~allowed_flags) { warn("Rule has invalid flags 0x%hhx", new->flags & ~allowed_flags); return -EINVAL; } - if (new->flags & FWD_DUAL_STACK_ANY && - !inany_equals(&new->addr, &inany_any6)) { - char astr[INANY_ADDRSTRLEN]; + if (new->flags & FWD_DUAL_STACK_ANY) { + if (!inany_equals(&new->addr, &inany_any6)) { + char astr[INANY_ADDRSTRLEN]; - warn("Dual stack rule has non-wildcard address %s", - inany_ntop(&new->addr, astr, sizeof(astr))); + warn("Dual stack rule has non-wildcard address %s", + inany_ntop(&new->addr, astr, sizeof(astr))); + return -EINVAL; + } + if (!(fwd->caps & FWD_CAP_IPV4)) { + warn("Dual stack forward, but IPv4 not enabled"); + return -EINVAL; + } + if (!(fwd->caps & FWD_CAP_IPV6)) { + warn("Dual stack forward, but IPv6 not enabled"); + return -EINVAL; + } + } else { + if (inany_v4(&new->addr) && !(fwd->caps & FWD_CAP_IPV4)) { + warn("IPv4 forward, but IPv4 not enabled"); + return -EINVAL; + } + if (!inany_v4(&new->addr) && !(fwd->caps & FWD_CAP_IPV6)) { + warn("IPv6 forward, but IPv6 not enabled"); + return -EINVAL; + } + } + if (new->proto == IPPROTO_TCP) { + if (!(fwd->caps & FWD_CAP_TCP)) { + warn("Can't add TCP forwarding rule, TCP not enabled"); + return -EINVAL; + } + } else if (new->proto == IPPROTO_UDP) { + if (!(fwd->caps & FWD_CAP_UDP)) { + warn("Can't add UDP forwarding rule, UDP not enabled"); + return -EINVAL; + } + } else { + warn("Unsupported protocol 0x%hhx (%s) for forwarding rule", + new->proto, ipproto_name(new->proto)); return -EINVAL; } -- 2.53.0

1 0

[PATCH v4 01/17] conf, fwd: Stricter rule checking in fwd_rule_add()
by David Gibson 21 Apr '26

21 Apr '26

Although fwd_rule_add() performs some sanity checks on the rule it is given, there are invalid rules we don't check for, assuming that its callers will do that. That won't be enough when we can get rules inserted by a dynamic update client without going through the existing parsing code. So, add stricter checks to fwd_rule_add(), which is now possible thanks to the capabilities bits in the struct fwd_table. Where those duplicate existing checks in the callers, remove the old copies. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- conf.c | 21 --------------------- fwd.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++----- 2 files changed, 47 insertions(+), 26 deletions(-) diff --git a/conf.c b/conf.c index 6e884e54..b470b0d8 100644 --- a/conf.c +++ b/conf.c @@ -176,8 +176,6 @@ static void conf_ports_range_except(struct fwd_table *fwd, uint8_t proto, die("Invalid interface name: %s", ifname); } - assert(first != 0); - for (base = first; base <= last; base++) { if (exclude && bitmap_isset(exclude, base)) continue; @@ -310,10 +308,6 @@ static void conf_ports_spec(struct fwd_table *fwd, uint8_t proto, if (p != ep) /* Garbage after the ranges */ goto bad; - if (orig_range.first == 0) { - die("Can't forward port 0 included in '%s'", spec); - } - conf_ports_range_except(fwd, proto, addr, ifname, orig_range.first, orig_range.last, exclude, @@ -356,11 +350,6 @@ static void conf_ports(char optname, const char *optarg, struct fwd_table *fwd) return; } - if (proto == IPPROTO_TCP && !(fwd->caps & FWD_CAP_TCP)) - die("TCP port forwarding requested but TCP is disabled"); - if (proto == IPPROTO_UDP && !(fwd->caps & FWD_CAP_UDP)) - die("UDP port forwarding requested but UDP is disabled"); - strncpy(buf, optarg, sizeof(buf) - 1); if ((spec = strchr(buf, '/'))) { @@ -405,16 +394,6 @@ static void conf_ports(char optname, const char *optarg, struct fwd_table *fwd) addr = NULL; } - if (addr) { - if (!(fwd->caps & FWD_CAP_IPV4) && inany_v4(addr)) { - die("IPv4 is disabled, can't use -%c %s", - optname, optarg); - } else if (!(fwd->caps & FWD_CAP_IPV6) && !inany_v4(addr)) { - die("IPv6 is disabled, can't use -%c %s", - optname, optarg); - } - } - if (optname == 'T' || optname == 'U') { assert(!addr && !ifname); diff --git a/fwd.c b/fwd.c index c7fd1a9d..979c1494 100644 --- a/fwd.c +++ b/fwd.c @@ -367,17 +367,59 @@ int fwd_rule_add(struct fwd_table *fwd, const struct fwd_rule *new) new->first, new->last); return -EINVAL; } + if (!new->first) { + warn("Forwarding rule attempts to map from port 0"); + return -EINVAL; + } + if (!new->to || + (in_port_t)(new->to + new->last - new->first) < new->to) { + warn("Forwarding rule attempts to map to port 0"); + return -EINVAL; + } if (new->flags & ~allowed_flags) { warn("Rule has invalid flags 0x%hhx", new->flags & ~allowed_flags); return -EINVAL; } - if (new->flags & FWD_DUAL_STACK_ANY && - !inany_equals(&new->addr, &inany_any6)) { - char astr[INANY_ADDRSTRLEN]; + if (new->flags & FWD_DUAL_STACK_ANY) { + if (!inany_equals(&new->addr, &inany_any6)) { + char astr[INANY_ADDRSTRLEN]; - warn("Dual stack rule has non-wildcard address %s", - inany_ntop(&new->addr, astr, sizeof(astr))); + warn("Dual stack rule has non-wildcard address %s", + inany_ntop(&new->addr, astr, sizeof(astr))); + return -EINVAL; + } + if (!(fwd->caps & FWD_CAP_IPV4)) { + warn("Dual stack forward, but IPv4 not enabled"); + return -EINVAL; + } + if (!(fwd->caps & FWD_CAP_IPV6)) { + warn("Dual stack forward, but IPv6 not enabled"); + return -EINVAL; + } + } else { + if (inany_v4(&new->addr) && !(fwd->caps & FWD_CAP_IPV4)) { + warn("IPv4 forward, but IPv4 not enabled"); + return -EINVAL; + } + if (!inany_v4(&new->addr) && !(fwd->caps & FWD_CAP_IPV6)) { + warn("IPv6 forward, but IPv6 not enabled"); + return -EINVAL; + } + } + if (new->proto == IPPROTO_TCP) { + if (!(fwd->caps & FWD_CAP_TCP)) { + warn("Can't add TCP forwarding rule, TCP not enabled"); + return -EINVAL; + } + } else if (new->proto == IPPROTO_UDP) { + if (!(fwd->caps & FWD_CAP_UDP)) { + warn("Can't add UDP forwarding rule, UDP not enabled"); + return -EINVAL; + } + } else { + warn("Unsupported protocol 0x%hhx (%s) for forwarding rule", + new->proto, ipproto_name(new->proto)); return -EINVAL; } -- 2.53.0

1 0

[PATCH v1] tcp: Handle errors from tcp_send_flag()
by Anshu Kumari 21 Apr '26

21 Apr '26

tcp_send_flag() can return error codes from tcp_prepare_flags() failing TCP_INFO, or from failure to collect buffers on the vhost-user path. These errors indicate the connection requires resetting. Most callers of tcp_send_flag() were ignoring the error code and carrying on as if nothing was wrong. Check the return value at each call site and handle the error appropriately: - in tcp_data_from_tap(), return -1 so the caller resets - in tcp_tap_handler(), goto reset - in tcp_timer_handler()/tcp_sock_handler()/tcp_conn_from_sock_finish(), call tcp_rst() and return - in tcp_tap_conn_from_sock(), set CLOSING flag (flow not yet active) - in tcp_keepalive(), call tcp_rst() and continue the loop - in tcp_flow_migrate_target_ext(), goto fail The call in tcp_rst_do() is left unchecked: we are already resetting, and tcp_sock_rst() still needs to run regardless. Bug: https://bugs.passt.top/show_bug.cgi?id=194 Signed-off-by: Anshu Kumari <anskuma(a)redhat.com> --- tcp.c | 59 ++++++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 44 insertions(+), 15 deletions(-) diff --git a/tcp.c b/tcp.c index 8ea9be8..9ce671a 100644 --- a/tcp.c +++ b/tcp.c @@ -1917,7 +1917,9 @@ static int tcp_data_from_tap(const struct ctx *c, struct tcp_tap_conn *conn, "keep-alive sequence: %u, previous: %u", seq, conn->seq_from_tap); - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) + return -1; + tcp_timer_ctl(c, conn); if (setsockopt(conn->sock, SOL_SOCKET, SO_KEEPALIVE, @@ -2043,14 +2045,16 @@ eintr: * Then swiftly looked away and left. */ conn->seq_from_tap = seq_from_tap; - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) + return -1; } if (errno == EINTR) goto eintr; if (errno == EAGAIN || errno == EWOULDBLOCK) { - tcp_send_flag(c, conn, ACK | DUP_ACK); + if (tcp_send_flag(c, conn, ACK | DUP_ACK)) + return -1; return p->count - idx; } @@ -2070,7 +2074,8 @@ out: */ if (conn->seq_dup_ack_approx != (conn->seq_from_tap & 0xff)) { conn->seq_dup_ack_approx = conn->seq_from_tap & 0xff; - tcp_send_flag(c, conn, ACK | DUP_ACK); + if (tcp_send_flag(c, conn, ACK | DUP_ACK)) + return -1; } return p->count - idx; } @@ -2084,7 +2089,8 @@ out: conn_event(c, conn, TAP_FIN_RCVD); } else { - tcp_send_flag(c, conn, ACK_IF_NEEDED); + if (tcp_send_flag(c, conn, ACK_IF_NEEDED)) + return -1; } return p->count - idx; @@ -2122,7 +2128,10 @@ static void tcp_conn_from_sock_finish(const struct ctx *c, return; } - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) { + tcp_rst(c, conn); + return; + } /* The client might have sent data already, which we didn't * dequeue waiting for SYN,ACK from tap -- check now. @@ -2308,7 +2317,9 @@ int tcp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af, goto reset; } - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) + goto reset; + conn_event(c, conn, SOCK_FIN_SENT); return 1; @@ -2388,7 +2399,9 @@ int tcp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af, } conn_event(c, conn, SOCK_FIN_SENT); - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) + goto reset; + ack_due = 0; /* If we received a FIN, but the socket is in TCP_ESTABLISHED @@ -2478,7 +2491,11 @@ static void tcp_tap_conn_from_sock(const struct ctx *c, union flow *flow, conn->wnd_from_tap = WINDOW_DEFAULT; - tcp_send_flag(c, conn, SYN); + if (tcp_send_flag(c, conn, SYN)) { + conn_flag(c, conn, CLOSING); + return; + } + conn_flag(c, conn, ACK_FROM_TAP_DUE); tcp_get_sndbuf(conn); @@ -2585,7 +2602,10 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref) return; if (conn->flags & ACK_TO_TAP_DUE) { - tcp_send_flag(c, conn, ACK_IF_NEEDED); + if (tcp_send_flag(c, conn, ACK_IF_NEEDED)) { + tcp_rst(c, conn); + return; + } tcp_timer_ctl(c, conn); } else if (conn->flags & ACK_FROM_TAP_DUE) { if (!(conn->events & ESTABLISHED)) { @@ -2598,7 +2618,10 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref) tcp_rst(c, conn); } else { flow_trace(conn, "SYN timeout, retry"); - tcp_send_flag(c, conn, SYN); + if (tcp_send_flag(c, conn, SYN)) { + tcp_rst(c, conn); + return; + } conn->retries++; conn_flag(c, conn, SYN_RETRIED); tcp_timer_ctl(c, conn); @@ -2662,8 +2685,11 @@ void tcp_sock_handler(const struct ctx *c, union epoll_ref ref, tcp_data_from_sock(c, conn); if (events & EPOLLOUT) { - if (tcp_update_seqack_wnd(c, conn, false, NULL)) - tcp_send_flag(c, conn, ACK); + if (tcp_update_seqack_wnd(c, conn, false, NULL) && + tcp_send_flag(c, conn, ACK)) { + tcp_rst(c, conn); + return; + } } return; @@ -2903,7 +2929,8 @@ static void tcp_keepalive(struct ctx *c, const struct timespec *now) if (conn->tap_inactive) { flow_dbg(conn, "No tap activity for least %us, send keepalive", KEEPALIVE_INTERVAL); - tcp_send_flag(c, conn, KEEPALIVE); + if (tcp_send_flag(c, conn, KEEPALIVE)) + tcp_rst(c, conn); } /* Ready to check fot next interval */ @@ -3926,7 +3953,9 @@ int tcp_flow_migrate_target_ext(struct ctx *c, struct tcp_tap_conn *conn, int fd if (tcp_set_peek_offset(conn, peek_offset)) goto fail; - tcp_send_flag(c, conn, ACK); + if (tcp_send_flag(c, conn, ACK)) + goto fail; + tcp_data_from_sock(c, conn); if ((rc = tcp_epoll_ctl(conn))) { -- 2.53.0

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