On Thu, Jul 06, 2023 at 08:49:03PM +0200, Jan Klemkow wrote:
> > @@ -109,6 +109,9 @@
> > #include <netinet/tcp.h>
> > #include <netinet/tcp_timer.h>
> > #include <netinet/tcp_var.h>
>
> I think is a merge bug, isn't it?
>
> > +#include <netinet/tcp.h>
> > +#include <netinet/tcp_timer.h>
> > +#include <netinet/tcp_var.h>
Right.
> > + error = tcp_if_output_tso(ifp, mp, dst, rt, ifcap, mtu);
> > + if (error || *mp == NULL)
> > + return error;
> > +
> > + if ((*mp)->m_pkthdr.len <= mtu) {
>
> I may miss something but...
>
> Couldn't you move the *_cksum_out() calls above the upper
> tcp_if_output_tso() call? And than remove the *_cksum_out() calls
> inside of tcp_if_output_tso()?
>
> Thus, there is just one place where we call them.
>
> > + switch (dst->sa_family) {
> > + case AF_INET:
> > + in_hdr_cksum_out(*mp, ifp);
> > + in_proto_cksum_out(*mp, ifp);
> > + break;
> > +#ifdef INET6
> > + case AF_INET6:
> > + in6_proto_cksum_out(*mp, ifp);
> > + break;
> > +#endif
There is the case in tcp_if_output_tso() where we call tcp_chopper().
Then checksum has to be calcualted after chopping. If I do it
always before tcp_if_output_tso(), we may caluclate it twice. Once
for the large packet and once for the small ones.
New diff without duplicate includes.
bluhm
Index: net/if.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/if.c,v
retrieving revision 1.704
diff -u -p -r1.704 if.c
--- net/if.c 6 Jul 2023 04:55:04 -0000 1.704
+++ net/if.c 6 Jul 2023 19:15:00 -0000
@@ -886,6 +886,57 @@ if_output_ml(struct ifnet *ifp, struct m
}
int
+if_output_tso(struct ifnet *ifp, struct mbuf **mp, struct sockaddr *dst,
+ struct rtentry *rt, u_int mtu)
+{
+ uint32_t ifcap;
+ int error;
+
+ switch (dst->sa_family) {
+ case AF_INET:
+ ifcap = IFCAP_TSOv4;
+ break;
+#ifdef INET6
+ case AF_INET6:
+ ifcap = IFCAP_TSOv6;
+ break;
+#endif
+ default:
+ unhandled_af(dst->sa_family);
+ }
+
+ /*
+ * Try to send with TSO first. When forwarding LRO may set
+ * maximium segment size in mbuf header. Chop TCP segment
+ * even if it would fit interface MTU to preserve maximum
+ * path MTU.
+ */
+ error = tcp_if_output_tso(ifp, mp, dst, rt, ifcap, mtu);
+ if (error || *mp == NULL)
+ return error;
+
+ if ((*mp)->m_pkthdr.len <= mtu) {
+ switch (dst->sa_family) {
+ case AF_INET:
+ in_hdr_cksum_out(*mp, ifp);
+ in_proto_cksum_out(*mp, ifp);
+ break;
+#ifdef INET6
+ case AF_INET6:
+ in6_proto_cksum_out(*mp, ifp);
+ break;
+#endif
+ }
+ error = ifp->if_output(ifp, *mp, dst, rt);
+ *mp = NULL;
+ return error;
+ }
+
+ /* mp still contains mbuf that has to be fragmented or dropped. */
+ return 0;
+}
+
+int
if_output_mq(struct ifnet *ifp, struct mbuf_queue *mq, unsigned int *total,
struct sockaddr *dst, struct rtentry *rt)
{
Index: net/if_var.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/if_var.h,v
retrieving revision 1.128
diff -u -p -r1.128 if_var.h
--- net/if_var.h 28 Jun 2023 11:49:49 -0000 1.128
+++ net/if_var.h 6 Jul 2023 19:12:39 -0000
@@ -329,6 +329,8 @@ int if_output_ml(struct ifnet *, struct
struct sockaddr *, struct rtentry *);
int if_output_mq(struct ifnet *, struct mbuf_queue *, unsigned int *,
struct sockaddr *, struct rtentry *);
+int if_output_tso(struct ifnet *, struct mbuf **, struct sockaddr *,
+ struct rtentry *, u_int);
int if_output_local(struct ifnet *, struct mbuf *, sa_family_t);
void if_rtrequest_dummy(struct ifnet *, int, struct rtentry *);
void p2p_rtrequest(struct ifnet *, int, struct rtentry *);
Index: net/pf.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/pf.c,v
retrieving revision 1.1182
diff -u -p -r1.1182 pf.c
--- net/pf.c 6 Jul 2023 04:55:05 -0000 1.1182
+++ net/pf.c 6 Jul 2023 19:12:39 -0000
@@ -6610,15 +6610,8 @@ pf_route(struct pf_pdesc *pd, struct pf_
ip = mtod(m0, struct ip *);
}
- if (ntohs(ip->ip_len) <= ifp->if_mtu) {
- in_hdr_cksum_out(m0, ifp);
- in_proto_cksum_out(m0, ifp);
- ifp->if_output(ifp, m0, sintosa(dst), rt);
- goto done;
- }
-
- if (tcp_if_output_tso(ifp, &m0, sintosa(dst), rt,
- IFCAP_TSOv4, ifp->if_mtu) || m0 == NULL)
+ if (if_output_tso(ifp, &m0, sintosa(dst), rt, ifp->if_mtu) ||
+ m0 == NULL)
goto done;
/*
@@ -6745,14 +6738,8 @@ pf_route6(struct pf_pdesc *pd, struct pf
goto done;
}
- if (m0->m_pkthdr.len <= ifp->if_mtu) {
- in6_proto_cksum_out(m0, ifp);
- ifp->if_output(ifp, m0, sin6tosa(dst), rt);
- goto done;
- }
-
- if (tcp_if_output_tso(ifp, &m0, sin6tosa(dst), rt,
- IFCAP_TSOv6, ifp->if_mtu) || m0 == NULL)
+ if (if_output_tso(ifp, &m0, sin6tosa(dst), rt, ifp->if_mtu) ||
+ m0 == NULL)
goto done;
ip6stat_inc(ip6s_cantfrag);
Index: netinet/ip_output.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/ip_output.c,v
retrieving revision 1.389
diff -u -p -r1.389 ip_output.c
--- netinet/ip_output.c 4 Jul 2023 10:48:19 -0000 1.389
+++ netinet/ip_output.c 6 Jul 2023 19:12:39 -0000
@@ -451,17 +451,9 @@ sendit:
#endif
/*
- * If small enough for interface, can just send directly.
+ * If TSO or small enough for interface, can just send directly.
*/
- if (ntohs(ip->ip_len) <= mtu) {
- in_hdr_cksum_out(m, ifp);
- in_proto_cksum_out(m, ifp);
- error = ifp->if_output(ifp, m, sintosa(dst), ro->ro_rt);
- goto done;
- }
-
- error = tcp_if_output_tso(ifp, &m, sintosa(dst), ro->ro_rt,
- IFCAP_TSOv4, mtu);
+ error = if_output_tso(ifp, &m, sintosa(dst), ro->ro_rt, mtu);
if (error || m == NULL)
goto done;
Index: netinet6/ip6_forward.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/ip6_forward.c,v
retrieving revision 1.111
diff -u -p -r1.111 ip6_forward.c
--- netinet6/ip6_forward.c 16 Jun 2023 19:18:56 -0000 1.111
+++ netinet6/ip6_forward.c 6 Jul 2023 19:12:39 -0000
@@ -319,25 +319,13 @@ reroute:
}
#endif
- error = tcp_if_output_tso(ifp, &m, sin6tosa(sin6), rt, IFCAP_TSOv6,
- ifp->if_mtu);
+ error = if_output_tso(ifp, &m, sin6tosa(sin6), rt, ifp->if_mtu);
if (error)
ip6stat_inc(ip6s_cantforward);
else if (m == NULL)
ip6stat_inc(ip6s_forward);
if (error || m == NULL)
goto senderr;
-
- /* Check the size after pf_test to give pf a chance to refragment. */
- if (m->m_pkthdr.len <= ifp->if_mtu) {
- in6_proto_cksum_out(m, ifp);
- error = ifp->if_output(ifp, m, sin6tosa(sin6), rt);
- if (error)
- ip6stat_inc(ip6s_cantforward);
- else
- ip6stat_inc(ip6s_forward);
- goto senderr;
- }
if (mcopy != NULL)
icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, ifp->if_mtu);
Index: netinet6/ip6_output.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/ip6_output.c,v
retrieving revision 1.278
diff -u -p -r1.278 ip6_output.c
--- netinet6/ip6_output.c 13 Jun 2023 19:34:12 -0000 1.278
+++ netinet6/ip6_output.c 6 Jul 2023 19:15:00 -0000
@@ -677,7 +677,8 @@ reroute:
* 2-a: send as is if tlen <= interface mtu
* 2-b: error if tlen > interface mtu
*/
- tlen = m->m_pkthdr.len;
+ tlen = ISSET(m->m_pkthdr.csum_flags, M_TCP_TSO) ?
+ m->m_pkthdr.ph_mss : m->m_pkthdr.len;
if (ISSET(m->m_pkthdr.csum_flags, M_IPV6_DF_OUT)) {
CLR(m->m_pkthdr.csum_flags, M_IPV6_DF_OUT);
@@ -686,9 +687,8 @@ reroute:
dontfrag = 1;
else
dontfrag = 0;
- if (dontfrag && /* case 2-b */
- (ISSET(m->m_pkthdr.csum_flags, M_TCP_TSO) ?
- m->m_pkthdr.ph_mss : tlen) > ifp->if_mtu) {
+
+ if (dontfrag && tlen > ifp->if_mtu) { /* case 2-b */
#ifdef IPSEC
if (ip_mtudisc)
ipsec_adjust_mtu(m, mtu);
@@ -701,15 +701,12 @@ reroute:
* transmit packet without fragmentation
*/
if (dontfrag || tlen <= mtu) { /* case 1-a and 2-a */
- in6_proto_cksum_out(m, ifp);
- error = ifp->if_output(ifp, m, sin6tosa(dst), ro->ro_rt);
- goto done;
+ error = if_output_tso(ifp, &m, sin6tosa(dst), ro->ro_rt,
+ ifp->if_mtu);
+ if (error || m == NULL)
+ goto done;
+ goto bad; /* should not happen */
}
-
- error = tcp_if_output_tso(ifp, &m, sin6tosa(dst), ro->ro_rt,
- IFCAP_TSOv6, mtu);
- if (error || m == NULL)
- goto done;
/*
* try to fragment the packet. case 1-b
