From: Alexander Bluhm Subject: parallel raw IP input To: tech@openbsd.org Date: Thu, 11 Apr 2024 22:24:39 +0200 Hi, As mvs@ mentioned, running raw IP in parallel is easier as it is less complex than UDP. Especially there is no socket splicing. So I fixed one race in rip_input() and reused my shared net lock ip_deliver() loop. The idea is that ip_deliver() may run with shared or exclusive net lock. The last parameter indicates the mode. If is is running with shared netlock and encounters a protocol that needs exclusive lock, the packet is queued. Before ip_ours() always queued the packet. Now it tries to deliver with shared net lock, and if that is not possible, it queues the packet. In case we have an IPv6 header chain that must switch from shared to exclusive processing, the next protocol and mbuf offset are stored in a mbuf tag. The only drawback is that we have very limited test coverage for raw IP. The ip_deliver() shared locking change works also with UDP, Hvroje has tested it in 2022. ok? bluhm Index: net/if_bridge.c =================================================================== RCS file: /data/mirror/openbsd/cvs/src/sys/net/if_bridge.c,v diff -u -p -r1.369 if_bridge.c --- net/if_bridge.c 13 Feb 2024 12:22:09 -0000 1.369 +++ net/if_bridge.c 11 Apr 2024 18:15:15 -0000 @@ -1600,7 +1600,7 @@ bridge_ipsec(struct ifnet *ifp, struct e off); tdb_unref(tdb); if (prot != IPPROTO_DONE) - ip_deliver(&m, &hlen, prot, af); + ip_deliver(&m, &hlen, prot, af, 0); return (1); } else { tdb_unref(tdb); Index: netinet/in_proto.c =================================================================== RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/in_proto.c,v diff -u -p -r1.103 in_proto.c --- netinet/in_proto.c 11 Jan 2024 14:15:12 -0000 1.103 +++ netinet/in_proto.c 11 Apr 2024 18:15:15 -0000 @@ -210,7 +210,7 @@ const struct protosw inetsw[] = { .pr_type = SOCK_RAW, .pr_domain = &inetdomain, .pr_protocol = IPPROTO_RAW, - .pr_flags = PR_ATOMIC|PR_ADDR, + .pr_flags = PR_ATOMIC|PR_ADDR|PR_MPINPUT, .pr_input = rip_input, .pr_ctloutput = rip_ctloutput, .pr_usrreqs = &rip_usrreqs, @@ -377,7 +377,7 @@ const struct protosw inetsw[] = { /* raw wildcard */ .pr_type = SOCK_RAW, .pr_domain = &inetdomain, - .pr_flags = PR_ATOMIC|PR_ADDR, + .pr_flags = PR_ATOMIC|PR_ADDR|PR_MPINPUT, .pr_input = rip_input, .pr_ctloutput = rip_ctloutput, .pr_usrreqs = &rip_usrreqs, Index: netinet/ip_input.c =================================================================== RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/ip_input.c,v diff -u -p -r1.391 ip_input.c --- netinet/ip_input.c 28 Feb 2024 10:57:20 -0000 1.391 +++ netinet/ip_input.c 11 Apr 2024 19:51:52 -0000 @@ -245,6 +245,30 @@ ip_ours(struct mbuf **mp, int *offp, int if (af != AF_UNSPEC) return nxt; + nxt = ip_deliver(mp, offp, nxt, AF_INET, 1); + if (nxt == IPPROTO_DONE) + return IPPROTO_DONE; + + /* save values for later, use after dequeue */ + if (*offp != sizeof(struct ip)) { + struct m_tag *mtag; + struct ipoffnxt *ion; + + /* mbuf tags are expensive, but only used for header options */ + mtag = m_tag_get(PACKET_TAG_IP_OFFNXT, sizeof(*ion), + M_NOWAIT); + if (mtag == NULL) { + ipstat_inc(ips_idropped); + m_freemp(mp); + return IPPROTO_DONE; + } + ion = (struct ipoffnxt *)(mtag + 1); + ion->ion_off = *offp; + ion->ion_nxt = nxt; + + m_tag_prepend(*mp, mtag); + } + niq_enqueue(&ipintrq, *mp); *mp = NULL; return IPPROTO_DONE; @@ -260,18 +284,31 @@ ipintr(void) struct mbuf *m; while ((m = niq_dequeue(&ipintrq)) != NULL) { - struct ip *ip; + struct m_tag *mtag; int off, nxt; #ifdef DIAGNOSTIC if ((m->m_flags & M_PKTHDR) == 0) panic("ipintr no HDR"); #endif - ip = mtod(m, struct ip *); - off = ip->ip_hl << 2; - nxt = ip->ip_p; + mtag = m_tag_find(m, PACKET_TAG_IP_OFFNXT, NULL); + if (mtag != NULL) { + struct ipoffnxt *ion; + + ion = (struct ipoffnxt *)(mtag + 1); + off = ion->ion_off; + nxt = ion->ion_nxt; + + m_tag_delete(m, mtag); + } else { + struct ip *ip; - nxt = ip_deliver(&m, &off, nxt, AF_INET); + ip = mtod(m, struct ip *); + off = ip->ip_hl << 2; + nxt = ip->ip_p; + } + + nxt = ip_deliver(&m, &off, nxt, AF_INET, 0); KASSERT(nxt == IPPROTO_DONE); } } @@ -675,15 +712,11 @@ ip_fragcheck(struct mbuf **mp, int *offp #endif int -ip_deliver(struct mbuf **mp, int *offp, int nxt, int af) +ip_deliver(struct mbuf **mp, int *offp, int nxt, int af, int shared) { - const struct protosw *psw; - int naf = af; #ifdef INET6 int nest = 0; -#endif /* INET6 */ - - NET_ASSERT_LOCKED_EXCLUSIVE(); +#endif /* * Tell launch routine the next header @@ -691,13 +724,41 @@ ip_deliver(struct mbuf **mp, int *offp, IPSTAT_INC(delivered); while (nxt != IPPROTO_DONE) { + const struct protosw *psw; + int naf; + + switch (af) { + case AF_INET: + psw = &inetsw[ip_protox[nxt]]; + break; +#ifdef INET6 + case AF_INET6: + psw = &inet6sw[ip6_protox[nxt]]; + break; +#endif + } + if (shared && !ISSET(psw->pr_flags, PR_MPINPUT)) { + /* delivery not finished, decrement counter, queue */ + switch (af) { + case AF_INET: + counters_dec(ipcounters, ips_delivered); + break; +#ifdef INET6 + case AF_INET6: + counters_dec(ip6counters, ip6s_delivered); + break; +#endif + } + break; + } + #ifdef INET6 if (af == AF_INET6 && ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) { ip6stat_inc(ip6s_toomanyhdr); goto bad; } -#endif /* INET6 */ +#endif /* * protection against faulty packet - there should be @@ -716,7 +777,7 @@ ip_deliver(struct mbuf **mp, int *offp, } } /* Otherwise, just fall through and deliver the packet */ -#endif /* IPSEC */ +#endif switch (nxt) { case IPPROTO_IPV4: @@ -728,17 +789,10 @@ ip_deliver(struct mbuf **mp, int *offp, naf = AF_INET6; ip6stat_inc(ip6s_delivered); break; -#endif /* INET6 */ - } - switch (af) { - case AF_INET: - psw = &inetsw[ip_protox[nxt]]; - break; -#ifdef INET6 - case AF_INET6: - psw = &inet6sw[ip6_protox[nxt]]; +#endif + default: + naf = af; break; -#endif /* INET6 */ } nxt = (*psw->pr_input)(mp, offp, nxt, af); af = naf; Index: netinet/ip_var.h =================================================================== RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/ip_var.h,v diff -u -p -r1.114 ip_var.h --- netinet/ip_var.h 5 Mar 2024 09:45:13 -0000 1.114 +++ netinet/ip_var.h 11 Apr 2024 18:15:15 -0000 @@ -198,6 +198,11 @@ struct ipq { struct in_addr ipq_src, ipq_dst; }; +struct ipoffnxt { + int ion_off; + int ion_nxt; +}; + /* flags passed to ip_output */ #define IP_FORWARDING 0x1 /* most of ip header exists */ #define IP_RAWOUTPUT 0x2 /* raw ip header exists */ @@ -254,7 +259,7 @@ int ip_sysctl(int *, u_int, void *, siz void ip_savecontrol(struct inpcb *, struct mbuf **, struct ip *, struct mbuf *); int ip_input_if(struct mbuf **, int *, int, int, struct ifnet *); -int ip_deliver(struct mbuf **, int *, int, int); +int ip_deliver(struct mbuf **, int *, int, int, int); void ip_forward(struct mbuf *, struct ifnet *, struct rtentry *, int); int rip_ctloutput(int, struct socket *, int, int, struct mbuf *); void rip_init(void); Index: netinet/raw_ip.c =================================================================== RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/raw_ip.c,v diff -u -p -r1.157 raw_ip.c --- netinet/raw_ip.c 5 Mar 2024 09:45:13 -0000 1.157 +++ netinet/raw_ip.c 11 Apr 2024 18:15:15 -0000 @@ -172,7 +172,13 @@ rip_input(struct mbuf **mp, int *offp, i TAILQ_FOREACH(inp, &rawcbtable.inpt_queue, inp_queue) { KASSERT(!ISSET(inp->inp_flags, INP_IPV6)); - if (inp->inp_socket->so_rcv.sb_state & SS_CANTRCVMORE) + /* + * Packet must not be inserted after disconnected wakeup + * call. To avoid race, check again when holding receive + * buffer mutex. + */ + if (ISSET(READ_ONCE(inp->inp_socket->so_rcv.sb_state), + SS_CANTRCVMORE)) continue; if (rtable_l2(inp->inp_rtableid) != rtable_l2(m->m_pkthdr.ph_rtableid)) @@ -219,21 +225,24 @@ rip_input(struct mbuf **mp, int *offp, i n = m_copym(m, 0, M_COPYALL, M_NOWAIT); if (n != NULL) { struct socket *so = inp->inp_socket; - int ret; + int ret = 0; if (inp->inp_flags & INP_CONTROLOPTS || so->so_options & SO_TIMESTAMP) ip_savecontrol(inp, &opts, ip, n); mtx_enter(&so->so_rcv.sb_mtx); - ret = sbappendaddr(so, &so->so_rcv, - sintosa(&ripsrc), n, opts); + if (!ISSET(inp->inp_socket->so_rcv.sb_state, + SS_CANTRCVMORE)) { + ret = sbappendaddr(so, &so->so_rcv, + sintosa(&ripsrc), n, opts); + } mtx_leave(&so->so_rcv.sb_mtx); if (ret == 0) { - /* should notify about lost packet */ m_freem(n); m_freem(opts); + ipstat_inc(ips_noproto); } else sorwakeup(so); } Index: netinet6/ip6_input.c =================================================================== RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/ip6_input.c,v diff -u -p -r1.259 ip6_input.c --- netinet6/ip6_input.c 28 Feb 2024 10:57:20 -0000 1.259 +++ netinet6/ip6_input.c 11 Apr 2024 18:15:15 -0000 @@ -166,11 +166,6 @@ ip6_init(void) #endif } -struct ip6_offnxt { - int ion_off; - int ion_nxt; -}; - /* * Enqueue packet for local delivery. Queuing is used as a boundary * between the network layer (input/forward path) running with @@ -190,10 +185,14 @@ ip6_ours(struct mbuf **mp, int *offp, in if (af != AF_UNSPEC) return nxt; + nxt = ip_deliver(mp, offp, nxt, AF_INET6, 1); + if (nxt == IPPROTO_DONE) + return IPPROTO_DONE; + /* save values for later, use after dequeue */ if (*offp != sizeof(struct ip6_hdr)) { struct m_tag *mtag; - struct ip6_offnxt *ion; + struct ipoffnxt *ion; /* mbuf tags are expensive, but only used for header options */ mtag = m_tag_get(PACKET_TAG_IP6_OFFNXT, sizeof(*ion), @@ -203,7 +202,7 @@ ip6_ours(struct mbuf **mp, int *offp, in m_freemp(mp); return IPPROTO_DONE; } - ion = (struct ip6_offnxt *)(mtag + 1); + ion = (struct ipoffnxt *)(mtag + 1); ion->ion_off = *offp; ion->ion_nxt = nxt; @@ -234,9 +233,9 @@ ip6intr(void) #endif mtag = m_tag_find(m, PACKET_TAG_IP6_OFFNXT, NULL); if (mtag != NULL) { - struct ip6_offnxt *ion; + struct ipoffnxt *ion; - ion = (struct ip6_offnxt *)(mtag + 1); + ion = (struct ipoffnxt *)(mtag + 1); off = ion->ion_off; nxt = ion->ion_nxt; @@ -248,7 +247,7 @@ ip6intr(void) off = sizeof(struct ip6_hdr); nxt = ip6->ip6_nxt; } - nxt = ip_deliver(&m, &off, nxt, AF_INET6); + nxt = ip_deliver(&m, &off, nxt, AF_INET6, 0); KASSERT(nxt == IPPROTO_DONE); } } Index: sys/mbuf.h =================================================================== RCS file: /data/mirror/openbsd/cvs/src/sys/sys/mbuf.h,v diff -u -p -r1.262 mbuf.h --- sys/mbuf.h 21 Feb 2024 13:42:06 -0000 1.262 +++ sys/mbuf.h 11 Apr 2024 18:15:15 -0000 @@ -471,6 +471,8 @@ struct m_tag *m_tag_next(struct mbuf *, #define PACKET_TAG_IPSEC_IN_DONE 0x0001 /* IPsec applied, in */ #define PACKET_TAG_IPSEC_OUT_DONE 0x0002 /* IPsec applied, out */ #define PACKET_TAG_IPSEC_FLOWINFO 0x0004 /* IPsec flowinfo */ +#define PACKET_TAG_IP_OFFNXT 0x0010 /* IPv4 offset and next proto */ +#define PACKET_TAG_IP6_OFFNXT 0x0020 /* IPv6 offset and next proto */ #define PACKET_TAG_WIREGUARD 0x0040 /* WireGuard data */ #define PACKET_TAG_GRE 0x0080 /* GRE processing done */ #define PACKET_TAG_DLT 0x0100 /* data link layer type */ @@ -479,7 +481,6 @@ struct m_tag *m_tag_next(struct mbuf *, #define PACKET_TAG_SRCROUTE 0x1000 /* IPv4 source routing options */ #define PACKET_TAG_TUNNEL 0x2000 /* Tunnel endpoint address */ #define PACKET_TAG_CARP_BAL_IP 0x4000 /* carp(4) ip balanced marker */ -#define PACKET_TAG_IP6_OFFNXT 0x8000 /* IPv6 offset and next proto */ #define MTAG_BITS \ ("\20\1IPSEC_IN_DONE\2IPSEC_OUT_DONE\3IPSEC_FLOWINFO" \ Index: sys/protosw.h =================================================================== RCS file: /data/mirror/openbsd/cvs/src/sys/sys/protosw.h,v diff -u -p -r1.65 protosw.h --- sys/protosw.h 3 Feb 2024 22:50:09 -0000 1.65 +++ sys/protosw.h 11 Apr 2024 18:15:15 -0000 @@ -132,6 +132,7 @@ struct protosw { #define PR_ABRTACPTDIS 0x0020 /* abort on accept(2) to disconnected socket */ #define PR_SPLICE 0x0040 /* socket splicing is possible */ +#define PR_MPINPUT 0x0080 /* input runs with shared netlock */ /* * The arguments to usrreq are: