Date: Sun, 3 Feb 2013 15:23:29 +0000 (UTC) From: "Andrey V. Elsukov" <ae@FreeBSD.org> To: src-committers@freebsd.org, svn-src-user@freebsd.org Subject: svn commit: r246287 - user/ae/inet6/sys/netinet6 Message-ID: <201302031523.r13FNTsL025740@svn.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: ae Date: Sun Feb 3 15:23:28 2013 New Revision: 246287 URL: http://svnweb.freebsd.org/changeset/base/246287 Log: Rework in6_selectsrc function. Move the source address selection algorithm's logic into separate function. Remove all dependencies from the embedded scope ids. Update the logic of algorithm according to the RFC 6724. Update IPv6 statistic related to the source address selection algorithm only for the rule, that has won. Modified: user/ae/inet6/sys/netinet6/in6_src.c Modified: user/ae/inet6/sys/netinet6/in6_src.c ============================================================================== --- user/ae/inet6/sys/netinet6/in6_src.c Sun Feb 3 15:09:40 2013 (r246286) +++ user/ae/inet6/sys/netinet6/in6_src.c Sun Feb 3 15:23:28 2013 (r246287) @@ -135,6 +135,7 @@ static int in6_selectif(struct sockaddr_ struct ifnet *, u_int); static struct in6_addrpolicy *lookup_addrsel_policy(struct sockaddr_in6 *); +static int lookup_policy_label(const struct sockaddr_in6 *); static void init_policy_queue(void); static int add_addrsel_policyent(struct in6_addrpolicy *); @@ -151,52 +152,163 @@ static int in6_srcaddrscope(const struct * If necessary, this function lookups the routing table and returns * an entry to the caller for later use. */ -#define REPLACE(r) do {\ - if ((r) < sizeof(V_ip6stat.ip6s_sources_rule) / \ - sizeof(V_ip6stat.ip6s_sources_rule[0])) /* check for safety */ \ - V_ip6stat.ip6s_sources_rule[(r)]++; \ - /* { \ - char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \ - printf("in6_selectsrc: replace %s with %s by %d\n", ia_best ? ip6_sprintf(ip6buf, &ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(ip6b, &ia->ia_addr.sin6_addr), (r)); \ - } */ \ - goto replace; \ -} while(0) -#define NEXT(r) do {\ - if ((r) < sizeof(V_ip6stat.ip6s_sources_rule) / \ - sizeof(V_ip6stat.ip6s_sources_rule[0])) /* check for safety */ \ - V_ip6stat.ip6s_sources_rule[(r)]++; \ - /* { \ - char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \ - printf("in6_selectsrc: keep %s against %s by %d\n", ia_best ? ip6_sprintf(ip6buf, &ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(ip6b, &ia->ia_addr.sin6_addr), (r)); \ - } */ \ - goto next; /* XXX: we can't use 'continue' here */ \ -} while(0) -#define BREAK(r) do { \ - if ((r) < sizeof(V_ip6stat.ip6s_sources_rule) / \ - sizeof(V_ip6stat.ip6s_sources_rule[0])) /* check for safety */ \ - V_ip6stat.ip6s_sources_rule[(r)]++; \ - goto out; /* XXX: we can't use 'break' here */ \ -} while(0) + +struct srcaddr_choice { + struct in6_ifaddr *ia; + int scope; + int label; + int rule; +}; + +struct dstaddr_props { + struct ifnet *ifp; + struct in6_addr *addr; + int scope; + int label; + int prefixlen; +}; + +#define REPLACE(r) { rule = r; goto replace; } +#define NEXT(r) { rule = r; goto next; } + +static int +srcaddrcmp(struct srcaddr_choice *c, const struct in6_ifaddr *ia, + struct dstaddr_props *dst, const struct ucred *cred, + const struct ip6_pktopts *opts) +{ + int srcscope, rule, label, prefer_tempaddr, prefixlen; + + /* Avoid unusable addresses */ + if ((ia->ia6_flags & (IN6_IFF_NOTREADY | IN6_IFF_DETACHED)) || + (ia->ia_ifp->if_flags & IFF_UP) == 0) + return (-1); + /* + * In any case, multicast addresses and the unspecified address + * MUST NOT be included in a candidate set. + */ + if (IN6_IS_ADDR_MULTICAST(IA6_IN6(ia)) || + IN6_IS_ADDR_UNSPECIFIED(IA6_IN6(ia))) + return (-1); + if (!V_ip6_use_deprecated && IFA6_IS_DEPRECATED(ia)) + return (-1); + /* If jailed, only take addresses of the jail into account. */ + if (cred != NULL && prison_check_ip6(cred, IA6_IN6(ia)) != 0) + return (-1); + /* Check scope zones */ + scope = in6_srcaddrscope(IA6_IN6(ia)); + if (in6_getscopezone(ia->ia_ifp, scope) != + in6_getscopezone(dst->ifp, dst->scope)) + return (-1) + label = ADDR_LABEL_NOTAPP; + prefixlen = -1; + /* Rule 1: Prefer same address. */ + if (IN6_ARE_ADDR_EQUAL(IA6_IN6(ia), dst->addr)) + REPLACE(1); + /* Rule 2: Prefer appropriate scope. */ + srcscope = in6_srcaddrscope(IA6_IN6(ia)); + if (c->ia == NULL) { + dst->label = lookup_policy_label(dst->addr); + REPLACE(0); + } + if (IN6_ARE_SCOPE_CMP(c->scope, srcscope) < 0) { + if (IN6_ARE_SCOPE_CMP(c->scope, dst->scope) < 0) + REPLACE(2); + NEXT(2); + } else if (IN6_ARE_SCOPE_CMP(srcscope, c->scope) < 0) { + if (IN6_ARE_SCOPE_CMP(srcscope, dst->scope) < 0) + NEXT(2); + REPLACE(2); + } + /* Rule 3: Avoid deprecated addresses. */ + if (!IFA6_IS_DEPRECATED(c->ia) && IFA6_IS_DEPRECATED(ia)) + NEXT(3); + if (IFA6_IS_DEPRECATED(c->ia) && !IFA6_IS_DEPRECATED(ia)) + REPLACE(3); + /* + * Rule 4: Prefer home addresses. + * XXX: This is a TODO. + */ + /* Rule 5: Prefer outgoing interface. */ + if (c->ia->ia_ifp == dst->ifp && ia->ia_ifp != dst->ifp) + NEXT(5); + if (c->ia->ia_ifp != dst->ifp && ia->ia_ifp == dst->ifp) + REPLACE(5); + /* + * Rule 5.5: Prefer addresses in a prefix advertised by + * the next-hop. + * XXX: not yet. + */ + /* Rule 6: Prefer matching label. */ + if (dst->label != ADDR_LABEL_NOTAPP) { + c->label = lookup_policy_label(IA6_IN6(c->ia)); + label = lookup_policy_label(IA6_IN6(ia)); + if (c->label == dst->label && label != dst->label) + NEXT(6); + if (label == dst->label && c->label != dst->label) + REPLACE(6); + } + /* Rule 7: Prefer temporary addresses. */ + if (opts == NULL || + opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) + prefer_tempaddr = V_ip6_prefer_tempaddr; + else if (opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_NOTPREFER) + prefer_tempaddr = 0; + else + prefer_tempaddr = 1; + if ((c->ia->ia6_flags & IN6_IFF_TEMPORARY) != 0 && + (ia->ia6_flags & IN6_IFF_TEMPORARY) == 0) { + if (prefer_tempaddr) + NEXT(7); + REPLACE(7); + } + if ((c->ia->ia6_flags & IN6_IFF_TEMPORARY) == 0 && + (ia->ia6_flags & IN6_IFF_TEMPORARY) != 0) { + if (prefer_tempaddr) + REPLACE(7); + NEXT(7); + } + /* Rule 8: Use longest matching prefix. */ + if (c->prefixlen < 0) + c->prefixlen = in6_matchlen(IA6_IN6(c->ia), dst->addr); + prefixlen = in6_matchlen(IA6_IN6(ia), dst->addr); + if (c->prefixlen > prefixlen) + NEXT(8); + if (prefixlen > c->prefixlen) + REPLACE(8); + return (-1); +replace: + /* debug output */ + c->ia = ia; + c->label = label; + c->scope = srcscope; + c->rule = rule; + c->prefixlen = prefixlen; + return (rule); +next: + /* debug output */ + return (rule); +} +#undef REPLACE +#undef NEXT int in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, struct inpcb *inp, struct route_in6 *ro, struct ucred *cred, struct ifnet **ifpp, struct in6_addr *srcp) { - struct in6_addr dst, tmp; - struct ifnet *ifp = NULL, *oifp = NULL; - struct in6_ifaddr *ia = NULL, *ia_best = NULL; - struct in6_pktinfo *pi = NULL; - int dst_scope = -1, best_scope = -1, best_matchlen = -1; - struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL; - u_int32_t odstzone; - int prefer_tempaddr; - int error; + struct dstaddr_props dstprops; + struct srcaddr_choice best; + struct in6_addr tmp; struct ip6_moptions *mopts; + struct in6_pktinfo *pi; + struct in6_ifaddr *ia; + struct ifaddr *ifa; + struct ifnet *ifp, *oifp; + int error; KASSERT(srcp != NULL, ("%s: srcp is NULL", __func__)); - dst = dstsock->sin6_addr; /* make a copy for local operation */ + ifp = oifp = NULL; if (ifpp) { /* * Save a possibly passed in ifp for in6_selectsrc. Only @@ -209,7 +321,6 @@ in6_selectsrc(struct sockaddr_in6 *dstso oifp = *ifpp; *ifpp = NULL; } - if (inp != NULL) { INP_LOCK_ASSERT(inp); mopts = inp->in6p_moptions; @@ -225,41 +336,37 @@ in6_selectsrc(struct sockaddr_in6 *dstso */ if (opts && (pi = opts->ip6po_pktinfo) && !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) { - struct in6_ifaddr *ia6; - /* get the outgoing interface */ if ((error = in6_selectif(dstsock, opts, mopts, ro, &ifp, oifp, (inp != NULL) ? inp->inp_inc.inc_fibnum : RT_DEFAULT_FIB)) != 0) return (error); KASSERT(ifp != NULL, ("%s: ifp is NULL", __func__)); - /* - * Determine the appropriate zone id of the source based on - * the zone of the destination and the outgoing interface. - */ - odstzone = in6_getscopezone(ifp, - in6_addrscope(&pi->ipi6_addr)); - /* XXX: prison_local_ip6 can override pi->ipi6_addr */ if (cred != NULL && (error = prison_local_ip6(cred, &pi->ipi6_addr, (inp != NULL && (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0))) != 0) return (error); - - ia6 = in6ifa_ifwithaddr(&pi->ipi6_addr, odstzone); - if (ia6 == NULL || - (ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY))) { - if (ia6 != NULL) - ifa_free(&ia6->ia_ifa); + /* + * Determine the appropriate zone id of the source based on + * the zone of the destination and the outgoing interface. + * Even if source address is explicitly specified, it can + * not break the destination zone. + */ + ia = in6ifa_ifwithaddr(&pi->ipi6_addr, in6_getscopezone( + ifp, in6_srcaddrscope(&dstsock.sin6_addr))); + if (ia == NULL || + (ia->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY))) { + if (ia != NULL) + ifa_free(&ia->ia_ifa); return (EADDRNOTAVAIL); } if (ifpp) *ifpp = ifp; - bcopy(&ia6->ia_addr.sin6_addr, srcp, sizeof(*srcp)); - ifa_free(&ia6->ia_ifa); + bcopy(IA6_IN6(ia), srcp, sizeof(*srcp)); + ifa_free(&ia->ia_ifa); return (0); } - /* * Otherwise, if the socket has already bound the source, just use it. */ @@ -271,14 +378,12 @@ in6_selectsrc(struct sockaddr_in6 *dstso bcopy(&inp->in6p_laddr, srcp, sizeof(*srcp)); return (0); } - /* * Bypass source address selection and use the primary jail IP * if requested. */ if (cred != NULL && !prison_saddrsel_ip6(cred, srcp)) return (0); - /* * If the address is not specified, choose the best one based on * the outgoing interface and the destination address. @@ -287,199 +392,45 @@ in6_selectsrc(struct sockaddr_in6 *dstso if ((error = in6_selectif(dstsock, opts, mopts, ro, &ifp, oifp, (inp != NULL) ? inp->inp_inc.inc_fibnum : RT_DEFAULT_FIB)) != 0) return (error); - -#ifdef DIAGNOSTIC - if (ifp == NULL) /* this should not happen */ - panic("in6_selectsrc: NULL ifp"); -#endif - error = in6_setscope(&dst, ifp, &odstzone); - if (error) - return (error); - - IN6_IFADDR_RLOCK(); - TAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) { - int new_scope = -1, new_matchlen = -1; - struct in6_addrpolicy *new_policy = NULL; - u_int32_t srczone, osrczone, dstzone; - struct in6_addr src; - struct ifnet *ifp1 = ia->ia_ifp; - - /* - * We'll never take an address that breaks the scope zone - * of the destination. We also skip an address if its zone - * does not contain the outgoing interface. - * XXX: we should probably use sin6_scope_id here. - */ - if (in6_setscope(&dst, ifp1, &dstzone) || - odstzone != dstzone) { - continue; - } - src = ia->ia_addr.sin6_addr; - if (in6_setscope(&src, ifp, &osrczone) || - in6_setscope(&src, ifp1, &srczone) || - osrczone != srczone) { - continue; - } - - /* avoid unusable addresses */ - if ((ia->ia6_flags & - (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) { + KASSERT(ifp != NULL, ("%s: ifp is NULL", __func__)); + /* + * RFC 6724 (section 4): + * For all multicast and link-local destination addresses, the set of + * candidate source addresses MUST only include addresses assigned to + * interfaces belonging to the same link as the outgoing interface. + */ + dstprops.ifp = ifp; + dstprops.addr = &dstsock.sin6_addr; + dstprops.scope = in6_srcaddrscope(&dstsock.sin6_addr); + best.rule = -1; + best.ia = NULL; + if (IN6_IS_ADDR_MULTICAST(&dstsock.sin6_addr) || + dstprops.scope == IPV6_ADDR_SCOPE_LINKLOCAL) { + IF_ADDR_RLOCK(ifp); + TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { + if (ifa->ifa_addr->sa_family != AF_INET6) continue; + ret = srcaddrcmp(&best, (struct in6_ifaddr*)ifa, + &dstprops, cred, opts); + if (ret == 1) + break; + } + if (best.rule >= 0) + ifa_ref(&best.ia->ia_ifa); + IF_ADDR_RUNLOCK(ifp); + } else { + IN6_IFADDR_RLOCK(); + TAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) { + ret = srcaddrcmp(&best, ia, &dstprops, cred, opts); + if (ret == 1) + break; } - if (!V_ip6_use_deprecated && IFA6_IS_DEPRECATED(ia)) - continue; - - /* If jailed only take addresses of the jail into account. */ - if (cred != NULL && - prison_check_ip6(cred, &ia->ia_addr.sin6_addr) != 0) - continue; - - /* Rule 1: Prefer same address */ - if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr)) { - ia_best = ia; - BREAK(1); /* there should be no better candidate */ - } - - if (ia_best == NULL) - REPLACE(0); - - /* Rule 2: Prefer appropriate scope */ - if (dst_scope < 0) - dst_scope = in6_addrscope(&dst); - new_scope = in6_addrscope(&ia->ia_addr.sin6_addr); - if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) { - if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0) - REPLACE(2); - NEXT(2); - } else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) { - if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0) - NEXT(2); - REPLACE(2); - } - - /* - * Rule 3: Avoid deprecated addresses. Note that the case of - * !ip6_use_deprecated is already rejected above. - */ - if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia)) - NEXT(3); - if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia)) - REPLACE(3); - - /* Rule 4: Prefer home addresses */ - /* - * XXX: This is a TODO. We should probably merge the MIP6 - * case above. - */ - - /* Rule 5: Prefer outgoing interface */ - if (!(ND_IFINFO(ifp)->flags & ND6_IFF_NO_PREFER_IFACE)) { - if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp) - NEXT(5); - if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp) - REPLACE(5); - } - - /* - * Rule 6: Prefer matching label - * Note that best_policy should be non-NULL here. - */ - if (dst_policy == NULL) - dst_policy = lookup_addrsel_policy(dstsock); - if (dst_policy->label != ADDR_LABEL_NOTAPP) { - new_policy = lookup_addrsel_policy(&ia->ia_addr); - if (dst_policy->label == best_policy->label && - dst_policy->label != new_policy->label) - NEXT(6); - if (dst_policy->label != best_policy->label && - dst_policy->label == new_policy->label) - REPLACE(6); - } - - /* - * Rule 7: Prefer public addresses. - * We allow users to reverse the logic by configuring - * a sysctl variable, so that privacy conscious users can - * always prefer temporary addresses. - */ - if (opts == NULL || - opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) { - prefer_tempaddr = V_ip6_prefer_tempaddr; - } else if (opts->ip6po_prefer_tempaddr == - IP6PO_TEMPADDR_NOTPREFER) { - prefer_tempaddr = 0; - } else - prefer_tempaddr = 1; - if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) && - (ia->ia6_flags & IN6_IFF_TEMPORARY)) { - if (prefer_tempaddr) - REPLACE(7); - else - NEXT(7); - } - if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) && - !(ia->ia6_flags & IN6_IFF_TEMPORARY)) { - if (prefer_tempaddr) - NEXT(7); - else - REPLACE(7); - } - - /* - * Rule 8: prefer addresses on alive interfaces. - * This is a KAME specific rule. - */ - if ((ia_best->ia_ifp->if_flags & IFF_UP) && - !(ia->ia_ifp->if_flags & IFF_UP)) - NEXT(8); - if (!(ia_best->ia_ifp->if_flags & IFF_UP) && - (ia->ia_ifp->if_flags & IFF_UP)) - REPLACE(8); - - /* - * Rule 14: Use longest matching prefix. - * Note: in the address selection draft, this rule is - * documented as "Rule 8". However, since it is also - * documented that this rule can be overridden, we assign - * a large number so that it is easy to assign smaller numbers - * to more preferred rules. - */ - new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst); - if (best_matchlen < new_matchlen) - REPLACE(14); - if (new_matchlen < best_matchlen) - NEXT(14); - - /* Rule 15 is reserved. */ - - /* - * Last resort: just keep the current candidate. - * Or, do we need more rules? - */ - continue; - - replace: - ia_best = ia; - best_scope = (new_scope >= 0 ? new_scope : - in6_addrscope(&ia_best->ia_addr.sin6_addr)); - best_policy = (new_policy ? new_policy : - lookup_addrsel_policy(&ia_best->ia_addr)); - best_matchlen = (new_matchlen >= 0 ? new_matchlen : - in6_matchlen(&ia_best->ia_addr.sin6_addr, - &dst)); - - next: - continue; - - out: - break; - } - - if ((ia = ia_best) == NULL) { + if (best.rule >= 0) + ifa_ref(&best.ia->ia_ifa); IN6_IFADDR_RUNLOCK(); - return (EADDRNOTAVAIL); } - + if (best.rule < 0) + return (EADDRNOTAVAIL); /* * At this point at least one of the addresses belonged to the jail * but it could still be, that we want to further restrict it, e.g. @@ -490,17 +441,15 @@ in6_selectsrc(struct sockaddr_in6 *dstso * Use tmp to not change ::1 on lo0 to the primary jail address. */ tmp = ia->ia_addr.sin6_addr; + ifa_free(&ia->ia_ifa); if (cred != NULL && prison_local_ip6(cred, &tmp, (inp != NULL && (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) { - IN6_IFADDR_RUNLOCK(); return (EADDRNOTAVAIL); } - if (ifpp) *ifpp = ifp; - + V_ip6stat.ip6s_sources_rule[best.rule]++; bcopy(&tmp, srcp, sizeof(*srcp)); - IN6_IFADDR_RUNLOCK(); return (0); } @@ -1182,3 +1131,10 @@ in6_srcaddrscope(const struct in6_addr * } return (in6_addrscope(addr)); } + +static int +lookup_policy_label(const struct sockaddr_in6 *sa6) +{ + + return (lookup_addrsel_policy(sa6)->label); +}
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201302031523.r13FNTsL025740>