Further simplify nd6_output_lle.
Currently we have 3 usage patterns: 1) nd6_output (most traffic flow, no lle supplied, lle RLOCK sufficient) 2) corner cases for output (no lle, STALE lle, so on). lle WLOCK needed. 3) nd* iunternal machinery (WLOCK'ed lle provided, perform packet queing). We separate case 1 and implement it inside its only customer - nd6_output. This leads to some code duplication (especialy SEND stuff, which should be hooked to output in a different way), but simplifies locking and control flow logic fir nd6_output_lle. Reviewed by: ae MFC after: 3 weeks Sponsored by: Yandex LLC
This commit is contained in:
melifaro
parent
ab3f62ff43
commit
dfdcfd9e83
@ -1832,34 +1832,114 @@ nd6_slowtimo(void *arg)
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CURVNET_RESTORE();
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}
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/*
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* IPv6 packet output - light version.
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* Checks if destination LLE exists and is in proper state
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* (e.g no modification required). If not true, fall back to
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* "heavy" version.
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*/
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int
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nd6_output(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
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nd6_output(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m,
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struct sockaddr_in6 *dst, struct rtentry *rt0)
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{
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struct llentry *ln = NULL;
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int error = 0;
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return (nd6_output_lle(ifp, origifp, m0, dst, rt0, NULL, NULL));
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/* discard the packet if IPv6 operation is disabled on the interface */
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if ((ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED)) {
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m_freem(m);
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return (ENETDOWN); /* better error? */
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}
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if (IN6_IS_ADDR_MULTICAST(&dst->sin6_addr))
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goto sendpkt;
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if (nd6_need_cache(ifp) == 0)
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goto sendpkt;
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IF_AFDATA_RLOCK(ifp);
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ln = nd6_lookup(&dst->sin6_addr, 0, ifp);
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IF_AFDATA_RUNLOCK(ifp);
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/*
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* Perform fast path for the following cases:
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* 1) lle state is REACHABLE
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* 2) lle state is DELAY (NS message sentNS message sent)
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*
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* Every other case involves lle modification, so we handle
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* them separately.
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*/
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if (ln == NULL || (ln->ln_state != ND6_LLINFO_REACHABLE &&
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ln->ln_state != ND6_LLINFO_DELAY)) {
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/* Fall back to slow processing path */
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if (ln != NULL)
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LLE_RUNLOCK(ln);
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return (nd6_output_lle(ifp, origifp, m, dst, rt0, NULL, NULL));
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}
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sendpkt:
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if (ln != NULL)
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LLE_RUNLOCK(ln);
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#ifdef MAC
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mac_netinet6_nd6_send(ifp, m);
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#endif
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/*
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* If called from nd6_ns_output() (NS), nd6_na_output() (NA),
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* icmp6_redirect_output() (REDIRECT) or from rip6_output() (RS, RA
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* as handled by rtsol and rtadvd), mbufs will be tagged for SeND
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* to be diverted to user space. When re-injected into the kernel,
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* send_output() will directly dispatch them to the outgoing interface.
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*/
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if (send_sendso_input_hook != NULL) {
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struct m_tag *mtag;
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struct ip6_hdr *ip6;
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int ip6len;
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mtag = m_tag_find(m, PACKET_TAG_ND_OUTGOING, NULL);
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if (mtag != NULL) {
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ip6 = mtod(m, struct ip6_hdr *);
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ip6len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
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/* Use the SEND socket */
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error = send_sendso_input_hook(m, ifp, SND_OUT,
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ip6len);
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/* -1 == no app on SEND socket */
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if (error == 0 || error != -1)
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return (error);
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}
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}
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m_clrprotoflags(m); /* Avoid confusing lower layers. */
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IP_PROBE(send, NULL, NULL, mtod(m, struct ip6_hdr *), ifp, NULL,
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mtod(m, struct ip6_hdr *));
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if ((ifp->if_flags & IFF_LOOPBACK) == 0)
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origifp = ifp;
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error = (*ifp->if_output)(origifp, m, (struct sockaddr *)dst, NULL);
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return (error);
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}
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/*
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* Note that I'm not enforcing any global serialization
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* lle state or asked changes here as the logic is too
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* complicated to avoid having to always acquire an exclusive
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* lock
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* KMM
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* Output IPv6 packet - heavy version.
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* Function assume that either
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* 1) destination LLE does not exist, is invalid or stale, so
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* ND6_EXCLUSIVE lock needs to be acquired
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* 2) destination lle is provided (with ND6_EXCLUSIVE lock),
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* in that case packets are queued in &chain.
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*
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*/
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int
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nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
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nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m,
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struct sockaddr_in6 *dst, struct rtentry *rt0, struct llentry *lle,
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struct mbuf **chain)
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{
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struct mbuf *m = m0;
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struct m_tag *mtag;
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struct llentry *ln = lle;
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struct ip6_hdr *ip6;
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int error = 0;
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int flags = 0;
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int has_lle = 0;
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int ip6len;
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#ifdef INVARIANTS
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@ -1877,30 +1957,26 @@ nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
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return (ENETDOWN); /* better error? */
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}
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if (lle != NULL)
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has_lle = 1;
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if (IN6_IS_ADDR_MULTICAST(&dst->sin6_addr))
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goto sendpkt;
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if (nd6_need_cache(ifp) == 0)
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goto sendpkt;
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/*
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* next hop determination. This routine is derived from ether_output.
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*/
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/*
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* Address resolution or Neighbor Unreachability Detection
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* for the next hop.
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* At this point, the destination of the packet must be a unicast
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* or an anycast address(i.e. not a multicast).
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*/
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flags = (lle != NULL) ? LLE_EXCLUSIVE : 0;
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if (ln == NULL) {
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retry:
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if (lle == NULL) {
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IF_AFDATA_RLOCK(ifp);
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ln = lla_lookup(LLTABLE6(ifp), flags, (struct sockaddr *)dst);
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lle = nd6_lookup(&dst->sin6_addr, ND6_EXCLUSIVE, ifp);
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IF_AFDATA_RUNLOCK(ifp);
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if ((ln == NULL) && nd6_is_addr_neighbor(dst, ifp)) {
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if ((lle == NULL) && nd6_is_addr_neighbor(dst, ifp)) {
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/*
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* Since nd6_is_addr_neighbor() internally calls nd6_lookup(),
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* the condition below is not very efficient. But we believe
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@ -1908,34 +1984,31 @@ nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
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*/
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flags = ND6_CREATE | ND6_EXCLUSIVE;
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IF_AFDATA_LOCK(ifp);
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ln = nd6_lookup(&dst->sin6_addr, flags, ifp);
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lle = nd6_lookup(&dst->sin6_addr, flags, ifp);
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IF_AFDATA_UNLOCK(ifp);
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}
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}
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if (ln == NULL) {
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if (lle == NULL) {
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if ((ifp->if_flags & IFF_POINTOPOINT) == 0 &&
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!(ND_IFINFO(ifp)->flags & ND6_IFF_PERFORMNUD)) {
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char ip6buf[INET6_ADDRSTRLEN];
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log(LOG_DEBUG,
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"nd6_output: can't allocate llinfo for %s "
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"(ln=%p)\n",
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ip6_sprintf(ip6buf, &dst->sin6_addr), ln);
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ip6_sprintf(ip6buf, &dst->sin6_addr), lle);
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m_freem(m);
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return (ENOBUFS);
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}
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goto sendpkt; /* send anyway */
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}
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LLE_WLOCK_ASSERT(lle);
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/* We don't have to do link-layer address resolution on a p2p link. */
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if ((ifp->if_flags & IFF_POINTOPOINT) != 0 &&
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ln->ln_state < ND6_LLINFO_REACHABLE) {
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if ((flags & LLE_EXCLUSIVE) == 0) {
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flags |= LLE_EXCLUSIVE;
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LLE_RUNLOCK(ln);
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goto retry;
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}
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ln->ln_state = ND6_LLINFO_STALE;
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nd6_llinfo_settimer_locked(ln, (long)V_nd6_gctimer * hz);
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lle->ln_state < ND6_LLINFO_REACHABLE) {
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lle->ln_state = ND6_LLINFO_STALE;
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nd6_llinfo_settimer_locked(lle, (long)V_nd6_gctimer * hz);
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}
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/*
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@ -1945,15 +2018,10 @@ nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
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* neighbor unreachability detection on expiration.
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* (RFC 2461 7.3.3)
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*/
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if (ln->ln_state == ND6_LLINFO_STALE) {
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if ((flags & LLE_EXCLUSIVE) == 0) {
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flags |= LLE_EXCLUSIVE;
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LLE_RUNLOCK(ln);
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goto retry;
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}
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ln->la_asked = 0;
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ln->ln_state = ND6_LLINFO_DELAY;
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nd6_llinfo_settimer_locked(ln, (long)V_nd6_delay * hz);
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if (lle->ln_state == ND6_LLINFO_STALE) {
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lle->la_asked = 0;
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lle->ln_state = ND6_LLINFO_DELAY;
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nd6_llinfo_settimer_locked(lle, (long)V_nd6_delay * hz);
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}
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/*
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@ -1961,7 +2029,7 @@ nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
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* (i.e. its link-layer address is already resolved), just
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* send the packet.
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*/
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if (ln->ln_state > ND6_LLINFO_INCOMPLETE)
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if (lle->ln_state > ND6_LLINFO_INCOMPLETE)
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goto sendpkt;
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/*
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@ -1971,23 +2039,15 @@ nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
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* does not exceed nd6_maxqueuelen. When it exceeds nd6_maxqueuelen,
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* the oldest packet in the queue will be removed.
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*/
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if (ln->ln_state == ND6_LLINFO_NOSTATE)
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ln->ln_state = ND6_LLINFO_INCOMPLETE;
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if (lle->ln_state == ND6_LLINFO_NOSTATE)
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lle->ln_state = ND6_LLINFO_INCOMPLETE;
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if ((flags & LLE_EXCLUSIVE) == 0) {
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flags |= LLE_EXCLUSIVE;
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LLE_RUNLOCK(ln);
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goto retry;
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}
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LLE_WLOCK_ASSERT(ln);
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if (ln->la_hold) {
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if (lle->la_hold != NULL) {
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struct mbuf *m_hold;
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int i;
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i = 0;
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for (m_hold = ln->la_hold; m_hold; m_hold = m_hold->m_nextpkt) {
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for (m_hold = lle->la_hold; m_hold; m_hold = m_hold->m_nextpkt){
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i++;
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if (m_hold->m_nextpkt == NULL) {
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m_hold->m_nextpkt = m;
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@ -1995,35 +2055,34 @@ nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
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}
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}
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while (i >= V_nd6_maxqueuelen) {
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m_hold = ln->la_hold;
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ln->la_hold = ln->la_hold->m_nextpkt;
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m_hold = lle->la_hold;
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lle->la_hold = lle->la_hold->m_nextpkt;
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m_freem(m_hold);
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i--;
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}
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} else {
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ln->la_hold = m;
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lle->la_hold = m;
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}
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/*
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* If there has been no NS for the neighbor after entering the
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* INCOMPLETE state, send the first solicitation.
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*/
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if (!ND6_LLINFO_PERMANENT(ln) && ln->la_asked == 0) {
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ln->la_asked++;
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if (!ND6_LLINFO_PERMANENT(lle) && lle->la_asked == 0) {
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lle->la_asked++;
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nd6_llinfo_settimer_locked(ln,
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nd6_llinfo_settimer_locked(lle,
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(long)ND_IFINFO(ifp)->retrans * hz / 1000);
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LLE_WUNLOCK(ln);
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nd6_ns_output(ifp, NULL, &dst->sin6_addr, ln, 0);
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if (lle != NULL && ln == lle)
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LLE_WUNLOCK(lle);
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nd6_ns_output(ifp, NULL, &dst->sin6_addr, lle, 0);
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if (has_lle != 0)
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LLE_WLOCK(lle);
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} else if (lle == NULL || ln != lle) {
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} else if (has_lle == 0) {
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/*
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* We did the lookup (no lle arg) so we
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* need to do the unlock here.
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*/
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LLE_WUNLOCK(ln);
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LLE_WUNLOCK(lle);
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}
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return (0);
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@ -2033,12 +2092,8 @@ nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
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* ln is valid and the caller did not pass in
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* an llentry
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*/
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if ((ln != NULL) && (lle == NULL)) {
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if (flags & LLE_EXCLUSIVE)
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LLE_WUNLOCK(ln);
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else
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LLE_RUNLOCK(ln);
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}
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if (lle != NULL && has_lle == 0)
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LLE_WUNLOCK(lle);
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#ifdef MAC
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mac_netinet6_nd6_send(ifp, m);
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@ -2072,7 +2127,7 @@ nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
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* a list of mbufs to send and transmit them in the caller
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* after the lock is dropped
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*/
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if (lle != NULL) {
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if (has_lle != 0) {
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if (*chain == NULL)
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*chain = m;
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else {
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