The branch stable/13 has been updated by melifaro: URL: https://cgit.FreeBSD.org/src/commit/?id=4151d8ccdc647fb0cc2cee35eae24dd873812348
commit 4151d8ccdc647fb0cc2cee35eae24dd873812348 Author: Alexander V. Chernikov <[email protected]> AuthorDate: 2021-08-06 08:27:22 +0000 Commit: Alexander V. Chernikov <[email protected]> CommitDate: 2021-09-07 21:02:58 +0000 [lltable] Restructure nd6 code. Factor out lltable locking logic from lltable_try_set_entry_addr() into a separate lltable_acquire_wlock(), so the latter can be used in other parts of the code w/o duplication. Create nd6_try_set_entry_addr() to avoid code duplication in nd6.c and nd6_nbr.c. Move lle creation logic from nd6_resolve_slow() into a separate nd6_get_llentry() to simplify the former. These changes serve as a pre-requisite for implementing RFC8950 (IPv4 prefixes with IPv6 nexthops). Differential Revision: https://reviews.freebsd.org/D31432 (cherry picked from commit 0b79b007ebfc250a8a7b928df268ada6f1c988c4) --- sys/net/if_llatbl.c | 40 +++++++++++------ sys/net/if_llatbl.h | 2 + sys/netinet6/nd6.c | 114 ++++++++++++++++++++++++++++++++----------------- sys/netinet6/nd6.h | 1 + sys/netinet6/nd6_nbr.c | 11 +---- 5 files changed, 105 insertions(+), 63 deletions(-) diff --git a/sys/net/if_llatbl.c b/sys/net/if_llatbl.c index 70baf58c2778..c656974c80ee 100644 --- a/sys/net/if_llatbl.c +++ b/sys/net/if_llatbl.c @@ -318,22 +318,18 @@ lltable_set_entry_addr(struct ifnet *ifp, struct llentry *lle, } /* - * Tries to update @lle link-level address. - * Since update requires AFDATA WLOCK, function - * drops @lle lock, acquires AFDATA lock and then acquires - * @lle lock to maintain lock order. + * Acquires lltable write lock. * - * Returns 1 on success. + * Returns true on success, with both lltable and lle lock held. + * On failure, false is returned and lle wlock is still held. */ -int -lltable_try_set_entry_addr(struct ifnet *ifp, struct llentry *lle, - const char *linkhdr, size_t linkhdrsize, int lladdr_off) +bool +lltable_acquire_wlock(struct ifnet *ifp, struct llentry *lle) { + NET_EPOCH_ASSERT(); /* Perform real LLE update */ /* use afdata WLOCK to update fields */ - LLE_WLOCK_ASSERT(lle); - LLE_ADDREF(lle); LLE_WUNLOCK(lle); IF_AFDATA_WLOCK(ifp); LLE_WLOCK(lle); @@ -344,17 +340,33 @@ lltable_try_set_entry_addr(struct ifnet *ifp, struct llentry *lle, */ if ((lle->la_flags & LLE_DELETED) != 0) { IF_AFDATA_WUNLOCK(ifp); - LLE_FREE_LOCKED(lle); - return (0); + return (false); } + return (true); +} + +/* + * Tries to update @lle link-level address. + * Since update requires AFDATA WLOCK, function + * drops @lle lock, acquires AFDATA lock and then acquires + * @lle lock to maintain lock order. + * + * Returns 1 on success. + */ +int +lltable_try_set_entry_addr(struct ifnet *ifp, struct llentry *lle, + const char *linkhdr, size_t linkhdrsize, int lladdr_off) +{ + + if (!lltable_acquire_wlock(ifp, lle)) + return (0); + /* Update data */ lltable_set_entry_addr(ifp, lle, linkhdr, linkhdrsize, lladdr_off); IF_AFDATA_WUNLOCK(ifp); - LLE_REMREF(lle); - return (1); } diff --git a/sys/net/if_llatbl.h b/sys/net/if_llatbl.h index 488f8b006315..ffbaa7a946bb 100644 --- a/sys/net/if_llatbl.h +++ b/sys/net/if_llatbl.h @@ -238,6 +238,8 @@ void lltable_fill_sa_entry(const struct llentry *lle, struct sockaddr *sa); struct ifnet *lltable_get_ifp(const struct lltable *llt); int lltable_get_af(const struct lltable *llt); +bool lltable_acquire_wlock(struct ifnet *ifp, struct llentry *lle); + int lltable_foreach_lle(struct lltable *llt, llt_foreach_cb_t *f, void *farg); /* diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c index 143629d44fdb..ea64b3a6c14c 100644 --- a/sys/netinet6/nd6.c +++ b/sys/netinet6/nd6.c @@ -1382,6 +1382,35 @@ nd6_is_addr_neighbor(const struct sockaddr_in6 *addr, struct ifnet *ifp) return (rc); } +/* + * Tries to update @lle address/prepend data with new @lladdr. + * + * Returns true on success. + * In any case, @lle is returned wlocked. + */ +bool +nd6_try_set_entry_addr(struct ifnet *ifp, struct llentry *lle, char *lladdr) +{ + u_char linkhdr[LLE_MAX_LINKHDR]; + size_t linkhdrsize; + int lladdr_off; + + LLE_WLOCK_ASSERT(lle); + + linkhdrsize = sizeof(linkhdr); + if (lltable_calc_llheader(ifp, AF_INET6, lladdr, + linkhdr, &linkhdrsize, &lladdr_off) != 0) { + return (false); + } + + if (!lltable_acquire_wlock(ifp, lle)) + return (false); + lltable_set_entry_addr(ifp, lle, linkhdr, linkhdrsize, lladdr_off); + IF_AFDATA_WUNLOCK(ifp); + + return (true); +} + /* * Free an nd6 llinfo entry. * Since the function would cause significant changes in the kernel, DO NOT @@ -2027,14 +2056,9 @@ nd6_cache_lladdr(struct ifnet *ifp, struct in6_addr *from, char *lladdr, * Record source link-layer address * XXX is it dependent to ifp->if_type? */ - linkhdrsize = sizeof(linkhdr); - if (lltable_calc_llheader(ifp, AF_INET6, lladdr, - linkhdr, &linkhdrsize, &lladdr_off) != 0) - return; - - if (lltable_try_set_entry_addr(ifp, ln, linkhdr, linkhdrsize, - lladdr_off) == 0) { + if (!nd6_try_set_entry_addr(ifp, ln, lladdr)) { /* Entry was deleted */ + LLE_WUNLOCK(ln); return; } @@ -2257,6 +2281,39 @@ nd6_resolve(struct ifnet *ifp, int is_gw, struct mbuf *m, return (nd6_resolve_slow(ifp, 0, m, dst6, desten, pflags, plle)); } +/* + * Finds or creates a new llentry for @addr. + * Returns wlocked llentry or NULL. + */ +static __noinline struct llentry * +nd6_get_llentry(struct ifnet *ifp, const struct in6_addr *addr) +{ + struct llentry *lle, *lle_tmp; + + lle = nd6_alloc(addr, 0, ifp); + if (lle == NULL) { + char ip6buf[INET6_ADDRSTRLEN]; + log(LOG_DEBUG, + "nd6_get_llentry: can't allocate llinfo for %s " + "(ln=%p)\n", + ip6_sprintf(ip6buf, addr), lle); + return (NULL); + } + + IF_AFDATA_WLOCK(ifp); + LLE_WLOCK(lle); + /* Prefer any existing entry over newly-created one */ + lle_tmp = nd6_lookup(addr, LLE_EXCLUSIVE, ifp); + if (lle_tmp == NULL) + lltable_link_entry(LLTABLE6(ifp), lle); + IF_AFDATA_WUNLOCK(ifp); + if (lle_tmp != NULL) { + lltable_free_entry(LLTABLE6(ifp), lle); + return (lle_tmp); + } else + return (lle); +} + /* * Do L2 address resolution for @sa_dst address. Stores found * address in @desten buffer. Copy of lle ln_flags can be also @@ -2273,7 +2330,7 @@ nd6_resolve_slow(struct ifnet *ifp, int flags, struct mbuf *m, const struct sockaddr_in6 *dst, u_char *desten, uint32_t *pflags, struct llentry **plle) { - struct llentry *lle = NULL, *lle_tmp; + struct llentry *lle = NULL; struct in6_addr *psrc, src; int send_ns, ll_len; char *lladdr; @@ -2286,39 +2343,16 @@ nd6_resolve_slow(struct ifnet *ifp, int flags, struct mbuf *m, * At this point, the destination of the packet must be a unicast * or an anycast address(i.e. not a multicast). */ - if (lle == NULL) { - lle = nd6_lookup(&dst->sin6_addr, LLE_EXCLUSIVE, ifp); - if ((lle == NULL) && nd6_is_addr_neighbor(dst, ifp)) { - /* - * Since nd6_is_addr_neighbor() internally calls nd6_lookup(), - * the condition below is not very efficient. But we believe - * it is tolerable, because this should be a rare case. - */ - lle = nd6_alloc(&dst->sin6_addr, 0, ifp); - if (lle == NULL) { - char ip6buf[INET6_ADDRSTRLEN]; - log(LOG_DEBUG, - "nd6_output: can't allocate llinfo for %s " - "(ln=%p)\n", - ip6_sprintf(ip6buf, &dst->sin6_addr), lle); - m_freem(m); - return (ENOBUFS); - } + lle = nd6_lookup(&dst->sin6_addr, LLE_EXCLUSIVE, ifp); + if ((lle == NULL) && nd6_is_addr_neighbor(dst, ifp)) { + /* + * Since nd6_is_addr_neighbor() internally calls nd6_lookup(), + * the condition below is not very efficient. But we believe + * it is tolerable, because this should be a rare case. + */ + lle = nd6_get_llentry(ifp, &dst->sin6_addr); + } - IF_AFDATA_WLOCK(ifp); - LLE_WLOCK(lle); - /* Prefer any existing entry over newly-created one */ - lle_tmp = nd6_lookup(&dst->sin6_addr, LLE_EXCLUSIVE, ifp); - if (lle_tmp == NULL) - lltable_link_entry(LLTABLE6(ifp), lle); - IF_AFDATA_WUNLOCK(ifp); - if (lle_tmp != NULL) { - lltable_free_entry(LLTABLE6(ifp), lle); - lle = lle_tmp; - lle_tmp = NULL; - } - } - } if (lle == NULL) { m_freem(m); return (ENOBUFS); diff --git a/sys/netinet6/nd6.h b/sys/netinet6/nd6.h index ee53acce840a..fe0f2b22cc48 100644 --- a/sys/netinet6/nd6.h +++ b/sys/netinet6/nd6.h @@ -376,6 +376,7 @@ int nd6_resolve(struct ifnet *, int, struct mbuf *, int nd6_ioctl(u_long, caddr_t, struct ifnet *); void nd6_cache_lladdr(struct ifnet *, struct in6_addr *, char *, int, int, int); +bool nd6_try_set_entry_addr(struct ifnet *ifp, struct llentry *lle, char *lladdr); struct mbuf *nd6_grab_holdchain(struct llentry *); int nd6_flush_holdchain(struct ifnet *, struct llentry *, struct mbuf *); int nd6_add_ifa_lle(struct in6_ifaddr *); diff --git a/sys/netinet6/nd6_nbr.c b/sys/netinet6/nd6_nbr.c index 0f18a38c37a1..974c454e93a5 100644 --- a/sys/netinet6/nd6_nbr.c +++ b/sys/netinet6/nd6_nbr.c @@ -770,16 +770,9 @@ nd6_na_input(struct mbuf *m, int off, int icmp6len) /* * Record link-layer address, and update the state. */ - linkhdrsize = sizeof(linkhdr); - if (lltable_calc_llheader(ifp, AF_INET6, lladdr, - linkhdr, &linkhdrsize, &lladdr_off) != 0) - return; - - if (lltable_try_set_entry_addr(ifp, ln, linkhdr, linkhdrsize, - lladdr_off) == 0) { - ln = NULL; + if (!nd6_try_set_entry_addr(ifp, ln, lladdr)) goto freeit; - } + EVENTHANDLER_INVOKE(lle_event, ln, LLENTRY_RESOLVED); if (is_solicited) nd6_llinfo_setstate(ln, ND6_LLINFO_REACHABLE); _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/dev-commits-src-all To unsubscribe, send any mail to "[email protected]"
