git: dd0e6bb996dc - main - tcp: Enable symmetric hashing by setting hash on outgoing conns

The branch main has been updated by gallatin:

URL: https://cgit.FreeBSD.org/src/commit/?id=dd0e6bb996dc46e1d91f3d9aef87979716479465

commit dd0e6bb996dc46e1d91f3d9aef87979716479465
Author:     Andrew Gallatin <gallatin@FreeBSD.org>
AuthorDate: 2025-11-22 14:29:35 +0000
Commit:     Andrew Gallatin <gallatin@FreeBSD.org>
CommitDate: 2025-11-22 14:29:35 +0000

    tcp: Enable symmetric hashing by setting hash on outgoing conns
    
    Now that we can trust NICs to supply an identical hash result
    to software, we can setup the inpcb hash on outgoing connections.
    This gives us symmetric hashing, meaning packets should enter
    and leave on the same NIC queue.
    
    Differential Revision:  https://reviews.freebsd.org/D53104
    Reviewed by: adrian, cc, kbowling, tuexen, zlei
    Sponsored by: Netflix
---
 sys/netinet/tcp_usrreq.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
index 4d1a6455d09e..aeb28cd6a144 100644
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -75,6 +75,7 @@
 #include <netinet/in.h>
 #include <netinet/in_kdtrace.h>
 #include <netinet/in_pcb.h>
+#include <netinet/in_rss.h>
 #include <netinet/in_systm.h>
 #include <netinet/in_var.h>
 #include <netinet/ip.h>
@@ -82,6 +83,7 @@
 #ifdef INET6
 #include <netinet/ip6.h>
 #include <netinet6/in6_pcb.h>
+#include <netinet6/in6_rss.h>
 #include <netinet6/ip6_var.h>
 #include <netinet6/scope6_var.h>
 #endif
@@ -1487,6 +1489,10 @@ tcp_connect(struct tcpcb *tp, struct sockaddr_in *sin, struct thread *td)
 	if (error != 0)
 		return (error);
 
+	/* set the hash on the connection */
+	rss_proto_software_hash_v4(inp->inp_faddr, inp->inp_laddr,
+	    inp->inp_fport, inp->inp_lport, IPPROTO_TCP,
+	    &inp->inp_flowid, &inp->inp_flowtype);
 	/*
 	 * Compute window scaling to request:
 	 * Scale to fit into sweet spot.  See tcp_syncache.c.
@@ -1532,6 +1538,10 @@ tcp6_connect(struct tcpcb *tp, struct sockaddr_in6 *sin6, struct thread *td)
 	if (error != 0)
 		return (error);
 
+	/* set the hash on the connection */
+	rss_proto_software_hash_v6(&inp->in6p_faddr,
+	    &inp->in6p_laddr, inp->inp_fport, inp->inp_lport, IPPROTO_TCP,
+	    &inp->inp_flowid, &inp->inp_flowtype);
 	/* Compute window scaling to request.  */
 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
 	    (TCP_MAXWIN << tp->request_r_scale) < sb_max)