On Fri, Jan 31, 2025 at 08:39:51PM +0100, Stefano
Brivio wrote:
For migration only: we need to store
'oport', our socket-side port,
as we establish a connection from the guest, so that we can bind the
same oport as source port in the migration target.
Use getsockname() to fetch that.
Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>
---
flow.c | 4 ++--
flow_table.h | 4 ++--
tcp.c | 24 +++++++++++++++++++++++-
3 files changed, 27 insertions(+), 5 deletions(-)
diff --git a/flow.c b/flow.c
index 5638ff1..506cbac 100644
--- a/flow.c
+++ b/flow.c
@@ -411,8 +411,8 @@ const struct flowside *flow_initiate_sa(union flow *flow, uint8_t
pif,
*
* Return: pointer to the target flowside information
*/
-const struct flowside *flow_target(const struct ctx *c, union flow *flow,
- uint8_t proto)
+struct flowside *flow_target(const struct ctx *c, union flow *flow,
+ uint8_t proto)
{
char estr[INANY_ADDRSTRLEN], fstr[INANY_ADDRSTRLEN];
struct flow_common *f = &flow->f;
diff --git a/flow_table.h b/flow_table.h
index 633805d..b107107 100644
--- a/flow_table.h
+++ b/flow_table.h
@@ -178,8 +178,8 @@ const struct flowside *flow_target_af(union flow *flow, uint8_t pif,
sa_family_t af,
const void *saddr, in_port_t sport,
const void *daddr, in_port_t dport);
-const struct flowside *flow_target(const struct ctx *c, union flow *flow,
- uint8_t proto);
+struct flowside *flow_target(const struct ctx *c, union flow *flow,
+ uint8_t proto);
union flow *flow_set_type(union flow *flow, enum flow_type type);
#define FLOW_SET_TYPE(flow_, t_, var_) (&flow_set_type((flow_), (t_))->var_)
diff --git a/tcp.c b/tcp.c
index 0bd2a02..4fd405b 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1471,6 +1471,8 @@ static void tcp_bind_outbound(const struct ctx *c,
* @opts: Pointer to start of options
* @optlen: Bytes in options: caller MUST ensure available length
* @now: Current timestamp
+ *
+ * #syscalls:vu getsockname
*/
static void tcp_conn_from_tap(const struct ctx *c, sa_family_t af,
const void *saddr, const void *daddr,
@@ -1479,9 +1481,10 @@ static void tcp_conn_from_tap(const struct ctx *c, sa_family_t
af,
{
in_port_t srcport = ntohs(th->source);
in_port_t dstport = ntohs(th->dest);
- const struct flowside *ini, *tgt;
+ const struct flowside *ini;
struct tcp_tap_conn *conn;
union sockaddr_inany sa;
+ struct flowside *tgt;
union flow *flow;
int s = -1, mss;
uint64_t hash;
@@ -1586,6 +1589,25 @@ static void tcp_conn_from_tap(const struct ctx *c, sa_family_t
af,
}
tcp_epoll_ctl(c, conn);
+
+ if (c->mode == MODE_VU) { /* To rebind to same oport after migration */
I suspect we'll want this local side information in more places in
future, but this is fine for now.
+ if (af == AF_INET) {
+ struct sockaddr_in s_in;
+ socklen_t sl;
+
+ sl = sizeof(s_in);
+ getsockname(s, (struct sockaddr *)&s_in, &sl);
+ tgt->oport = ntohs(s_in.sin_port);
Since we're already doing the getsockname() we should also update
tgt->oaddr, and that might matter in cases where the host has multiple
local addresses.
+ } else {
+ struct sockaddr_in6 s_in6;
+ socklen_t sl;
+
+ sl = sizeof(s_in6);
+ getsockname(s, (struct sockaddr *)&s_in6, &sl);
+ tgt->oport = ntohs(s_in6.sin6_port);
+ }
We should add an inany_getsockname() or something helper for this. In
fact I'm pretty sure I wrote one at some point, but it was lost in the
shuffles of various flow table iterations.
I guess it can be a follow-up. Noted, anyway.
--
Stefano