Re: [PATCH 18/18] tap: Convert to iov_tail

On Wed, Apr 02, 2025 at 07:23:43PM +0200, Laurent Vivier wrote:

Use packet_base() and extract headers using IOV_REMOVE_HEADER() and IOV_PEEK_HEADER() rather than packet_get().

Patch description is a duplicate of 16/18, which is kind of confusing.

Remove packet_get() as it is not used anymore.

Signed-off-by: Laurent Vivier --- packet.c | 53 ----------------------------------------------------- packet.h | 10 ---------- tap.c | 23 ++++++++++++++--------- 3 files changed, 14 insertions(+), 72 deletions(-)

diff --git a/packet.c b/packet.c index 8066ac12502b..e917b0daad2a 100644 --- a/packet.c +++ b/packet.c @@ -103,59 +103,6 @@ void packet_add_do(struct pool *p, struct iov_tail *data, p->count++; }

-/** - * packet_get_do() - Get data range from packet descriptor from given pool - * @p: Packet pool - * @idx: Index of packet descriptor in pool - * @offset: Offset of data range in packet descriptor - * @len: Length of desired data range - * @left: Length of available data after range, set on return, can be NULL - * @func: For tracing: name of calling function, NULL means no trace() - * @line: For tracing: caller line of function call - * - * Return: pointer to start of data range, NULL on invalid range or descriptor - */ -void *packet_get_do(const struct pool *p, size_t idx, size_t offset, - size_t len, size_t *left, const char *func, int line) -{ - char *ptr; - - if (idx >= p->size || idx >= p->count) { - if (func) { - trace("packet %zu from pool size: %zu, count: %zu, " - "%s:%i", idx, p->size, p->count, func, line); - } - return NULL; - } - - if (len > PACKET_MAX_LEN) { - if (func) { - trace("packet data length %zu, %s:%i", - len, func, line); - } - return NULL; - } - - if (len + offset > p->pkt[idx].iov_len) { - if (func) { - trace("data length %zu, offset %zu from length %zu, " - "%s:%i", len, offset, p->pkt[idx].iov_len, - func, line); - } - return NULL; - } - - ptr = (char *)p->pkt[idx].iov_base + offset; - - if (packet_check_range(p, ptr, len, func, line)) - return NULL; - - if (left) - *left = p->pkt[idx].iov_len - offset - len; - - return ptr; -} - /** * packet_base_do() - Get data range from packet descriptor from given pool * @p: Packet pool diff --git a/packet.h b/packet.h index 35058e747a43..787535a228a5 100644 --- a/packet.h +++ b/packet.h @@ -32,9 +32,6 @@ struct pool { int vu_packet_check_range(void *buf, const char *ptr, size_t len); void packet_add_do(struct pool *p, struct iov_tail *data, const char *func, int line); -void *packet_get_do(const struct pool *p, const size_t idx, - size_t offset, size_t len, size_t *left, - const char *func, int line); bool packet_base_do(const struct pool *p, const size_t idx, struct iov_tail *data, const char *func, int line); @@ -43,13 +40,6 @@ void pool_flush(struct pool *p); #define packet_add(p, data) \ packet_add_do(p, data, __func__, __LINE__)

-#define packet_get(p, idx, offset, len, left) \ - packet_get_do(p, idx, offset, len, left, __func__, __LINE__) - - -#define packet_get_try(p, idx, offset, len, left) \ - packet_get_do(p, idx, offset, len, left, NULL, 0) - #define packet_base(p, idx, data) \ packet_base_do(p, idx, data, __func__, __LINE__)

diff --git a/tap.c b/tap.c index 280a04981954..d6a1da8481a2 100644 --- a/tap.c +++ b/tap.c @@ -870,17 +870,24 @@ resume: const struct udphdr *uh; struct iov_tail data; struct ipv6hdr *ip6h; + struct ipv6hdr ip6hc; + struct ethhdr ehc; + struct udphdr uhc; uint8_t proto; - char *l4h;

- eh = packet_get(in, i, 0, sizeof(*eh), NULL); + if (!packet_base(in, i, &data)) + return -1; + + eh = IOV_REMOVE_HEADER(&data, ehc); if (!eh) continue;

- ip6h = packet_get(in, i, sizeof(*eh), sizeof(*ip6h), &check); + ip6h = IOV_PEEK_HEADER(&data, ip6hc); if (!ip6h) continue;

+ check = iov_tail_size(&data) - sizeof(*ip6h); + saddr = &ip6h->saddr; daddr = &ip6h->daddr;

@@ -888,10 +895,8 @@ resume: if (plen != check) continue;

- data = IOV_TAIL_FROM_BUF(ip6h, sizeof(*ip6h) + check, 0); if (!ipv6_l4hdr(&data, &proto, &l4len)) continue; - l4h = (char *)data.iov[0].iov_base + data.off;

if (IN6_IS_ADDR_LOOPBACK(saddr) || IN6_IS_ADDR_LOOPBACK(daddr)) { char sstr[INET6_ADDRSTRLEN], dstr[INET6_ADDRSTRLEN]; @@ -916,6 +921,8 @@ resume: }

if (proto == IPPROTO_ICMPV6) { + const struct icmp6hdr *l4h; + struct icmp6hdr l4hc; PACKET_POOL_P(pkt, 1, in->buf, in->buf_size);

if (c->no_icmp) @@ -924,9 +931,9 @@ resume: if (l4len < sizeof(struct icmp6hdr)) continue;

- data = IOV_TAIL_FROM_BUF(l4h, l4len, 0); packet_add(pkt, &data);

+ l4h = IOV_PEEK_HEADER(&data, l4hc); if (ndp(c, (struct icmp6hdr *)l4h, saddr, pkt)) continue;

@@ -939,12 +946,11 @@ resume:

if (l4len < sizeof(*uh)) continue;

Shouldn't need this explicit check - peek_header will do it for you.

- uh = (struct udphdr *)l4h; + uh = IOV_PEEK_HEADER(&data, uhc);

if (proto == IPPROTO_UDP) { PACKET_POOL_P(pkt, 1, in->buf, in->buf_size);

- data = IOV_TAIL_FROM_BUF(l4h, l4len, 0); packet_add(pkt, &data);

if (dhcpv6(c, pkt, saddr, daddr)) @@ -999,7 +1005,6 @@ resume: #undef L4_SET

append: - data = IOV_TAIL_FROM_BUF(l4h, l4len, 0); packet_add((struct pool *)&seq->p, &data); }

-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson