From 9fe08d77b1f2f7b8812f8eaf61aa0b224b419fa6 Mon Sep 17 00:00:00 2001 From: ume Date: Wed, 2 Jun 2004 06:49:36 +0000 Subject: use source address as a hint to determine destination address by getipnodebyname(). --- lib/libc/net/name6.c | 411 ++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 361 insertions(+), 50 deletions(-) (limited to 'lib') diff --git a/lib/libc/net/name6.c b/lib/libc/net/name6.c index c71511d..d97cbab 100644 --- a/lib/libc/net/name6.c +++ b/lib/libc/net/name6.c @@ -106,6 +106,7 @@ __FBSDID("$FreeBSD$"); #include #include #include +#include #include /* XXX */ #endif @@ -178,6 +179,28 @@ struct policyqueue { }; TAILQ_HEAD(policyhead, policyqueue); +#define AIO_SRCFLAG_DEPRECATED 0x1 + +struct hp_order { + union { + struct sockaddr_storage aiou_ss; + struct sockaddr aiou_sa; + } aio_src_un; +#define aio_srcsa aio_src_un.aiou_sa + u_int32_t aio_srcflag; + int aio_srcscope; + int aio_dstscope; + struct policyqueue *aio_srcpolicy; + struct policyqueue *aio_dstpolicy; + union { + struct sockaddr_storage aiou_ss; + struct sockaddr aiou_sa; + } aio_un; +#define aio_sa aio_un.aiou_sa + int aio_matchlen; + u_char *aio_h_addr; +}; + static struct hostent *_hpcopy(struct hostent *hp, int *errp); static struct hostent *_hpaddr(int af, const char *name, void *addr, int *errp); static struct hostent *_hpmerge(struct hostent *hp1, struct hostent *hp2, int *errp); @@ -194,6 +217,10 @@ static int get_addrselectpolicy(struct policyhead *); static void free_addrselectpolicy(struct policyhead *); static struct policyqueue *match_addrselectpolicy(struct sockaddr *, struct policyhead *); +static void set_source(struct hp_order *, struct policyhead *); +static int matchlen(struct sockaddr *, struct sockaddr *); +static int comp_dst(const void *, const void *); +static int gai_addr2scopetype(struct sockaddr *); static FILE *_files_open(int *errp); static int _files_ghbyname(void *, void *, va_list); @@ -784,80 +811,90 @@ _hgetword(char **pp) static struct hostent * _hpreorder(struct hostent *hp) { - int i, j, n; - u_char *ap, **pp; - struct policyqueue *dstpolicy[MAXADDRS], *t; - struct sockaddr_storage ss; + struct hp_order *aio; + int i, n; + u_char *ap; + struct sockaddr *sa; struct policyhead policyhead; - if (hp == NULL || hp->h_addr_list[1] == NULL) + if (hp == NULL) return hp; + switch (hp->h_addrtype) { + case AF_INET: +#ifdef INET6 + case AF_INET6: +#endif + break; + default: + free_addrselectpolicy(&policyhead); + return hp; + } + + /* count the number of addrinfo elements for sorting. */ + for (n = 0; hp->h_addr_list[n] != NULL; n++) + ; + + /* + * If the number is small enough, we can skip the reordering process. + */ + if (n <= 1) + return hp; + + /* allocate a temporary array for sort and initialization of it. */ + if ((aio = malloc(sizeof(*aio) * n)) == NULL) + return hp; /* give up reordering */ + memset(aio, 0, sizeof(*aio) * n); + /* retrieve address selection policy from the kernel */ TAILQ_INIT(&policyhead); if (!get_addrselectpolicy(&policyhead)) { /* no policy is installed into kernel, we don't sort. */ + free(aio); return hp; } - switch (hp->h_addrtype) { - case AF_INET: - for (i = 0; (ap = (u_char *)hp->h_addr_list[i]); i++) { - memset(&ss, 0, sizeof(ss)); - ss.ss_family = AF_INET; - ss.ss_len = sizeof(struct sockaddr_in); - memcpy(&((struct sockaddr_in *)&ss)->sin_addr, ap, + for (i = 0; i < n; i++) { + ap = (u_char *)hp->h_addr_list[i]; + aio[i].aio_h_addr = ap; + sa = &aio[i].aio_sa; + switch (hp->h_addrtype) { + case AF_INET: + sa->sa_family = AF_INET; + sa->sa_len = sizeof(struct sockaddr_in); + memcpy(&((struct sockaddr_in *)sa)->sin_addr, ap, sizeof(struct in_addr)); - dstpolicy[i] = match_addrselectpolicy( - (struct sockaddr *)&ss, &policyhead); - } - break; + break; #ifdef INET6 - case AF_INET6: - for (i = 0; (ap = (u_char *)hp->h_addr_list[i]); i++) { - memset(&ss, 0, sizeof(ss)); + case AF_INET6: if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ap)) { - ss.ss_family = AF_INET; - ss.ss_len = sizeof(struct sockaddr_in); - memcpy(&((struct sockaddr_in *)&ss)->sin_addr, + sa->sa_family = AF_INET; + sa->sa_len = sizeof(struct sockaddr_in); + memcpy(&((struct sockaddr_in *)sa)->sin_addr, &ap[12], sizeof(struct in_addr)); } else { - ss.ss_family = AF_INET6; - ss.ss_len = sizeof(struct sockaddr_in6); - memcpy( - &((struct sockaddr_in6 *)&ss)->sin6_addr, + sa->sa_family = AF_INET6; + sa->sa_len = sizeof(struct sockaddr_in6); + memcpy(&((struct sockaddr_in6 *)sa)->sin6_addr, ap, sizeof(struct in6_addr)); } - dstpolicy[i] = match_addrselectpolicy( - (struct sockaddr *)&ss, &policyhead); - } - break; + break; #endif - default: - free_addrselectpolicy(&policyhead); - return hp; + } + aio[i].aio_dstscope = gai_addr2scopetype(sa); + aio[i].aio_dstpolicy = match_addrselectpolicy(sa, &policyhead); + set_source(&aio[i], &policyhead); } /* perform sorting. */ - n = i; - pp = (u_char **)hp->h_addr_list; - for (i = 0; i < n - 1; i++) { - for (j = i + 1; j < n; j++) { - if (dstpolicy[j] && - (dstpolicy[i] == NULL || - dstpolicy[j]->pc_policy.preced > - dstpolicy[i]->pc_policy.preced)) { - ap = pp[i]; - pp[i] = pp[j]; - pp[j] = ap; - t = dstpolicy[i]; - dstpolicy[i] = dstpolicy[j]; - dstpolicy[j] = t; - } - } - } + qsort(aio, n, sizeof(*aio), comp_dst); + + /* reorder the h_addr_list. */ + for (i = 0; i < n; i++) + hp->h_addr_list[i] = aio[i].aio_h_addr; /* cleanup and return */ + free(aio); free_addrselectpolicy(&policyhead); return hp; } @@ -982,6 +1019,280 @@ match_addrselectpolicy(addr, head) } +static void +set_source(aio, ph) + struct hp_order *aio; + struct policyhead *ph; +{ + struct sockaddr_storage ss = aio->aio_un.aiou_ss; + int s, srclen; + + /* set unspec ("no source is available"), just in case */ + aio->aio_srcsa.sa_family = AF_UNSPEC; + aio->aio_srcscope = -1; + + switch(ss.ss_family) { + case AF_INET: + ((struct sockaddr_in *)&ss)->sin_port = htons(1); + break; +#ifdef INET6 + case AF_INET6: + ((struct sockaddr_in6 *)&ss)->sin6_port = htons(1); + break; +#endif + default: /* ignore unsupported AFs explicitly */ + return; + } + + /* open a socket to get the source address for the given dst */ + if ((s = _socket(ss.ss_family, SOCK_DGRAM, IPPROTO_UDP)) < 0) + return; /* give up */ + if (_connect(s, (struct sockaddr *)&ss, ss.ss_len) < 0) + goto cleanup; + srclen = ss.ss_len; + if (_getsockname(s, &aio->aio_srcsa, &srclen) < 0) { + aio->aio_srcsa.sa_family = AF_UNSPEC; + goto cleanup; + } + aio->aio_srcscope = gai_addr2scopetype(&aio->aio_srcsa); + aio->aio_srcpolicy = match_addrselectpolicy(&aio->aio_srcsa, ph); + aio->aio_matchlen = matchlen(&aio->aio_srcsa, (struct sockaddr *)&ss); +#ifdef INET6 + if (ss.ss_family == AF_INET6) { + struct in6_ifreq ifr6; + u_int32_t flags6; + + /* XXX: interface name should not be hardcoded */ + strncpy(ifr6.ifr_name, "lo0", sizeof(ifr6.ifr_name)); + memset(&ifr6, 0, sizeof(ifr6)); + memcpy(&ifr6.ifr_addr, &ss, ss.ss_len); + if (_ioctl(s, SIOCGIFAFLAG_IN6, &ifr6) == 0) { + flags6 = ifr6.ifr_ifru.ifru_flags6; + if ((flags6 & IN6_IFF_DEPRECATED)) + aio->aio_srcflag |= AIO_SRCFLAG_DEPRECATED; + } + } +#endif + + cleanup: + _close(s); + return; +} + +static int +matchlen(src, dst) + struct sockaddr *src, *dst; +{ + int match = 0; + u_char *s, *d; + u_char *lim, r; + int addrlen; + + switch (src->sa_family) { +#ifdef INET6 + case AF_INET6: + s = (u_char *)&((struct sockaddr_in6 *)src)->sin6_addr; + d = (u_char *)&((struct sockaddr_in6 *)dst)->sin6_addr; + addrlen = sizeof(struct in6_addr); + lim = s + addrlen; + break; +#endif + case AF_INET: + s = (u_char *)&((struct sockaddr_in6 *)src)->sin6_addr; + d = (u_char *)&((struct sockaddr_in6 *)dst)->sin6_addr; + addrlen = sizeof(struct in_addr); + lim = s + addrlen; + break; + default: + return(0); + } + + while (s < lim) + if ((r = (*d++ ^ *s++)) != 0) { + while (r < addrlen * 8) { + match++; + r <<= 1; + } + break; + } else + match += 8; + return(match); +} + +static int +comp_dst(arg1, arg2) + const void *arg1, *arg2; +{ + const struct hp_order *dst1 = arg1, *dst2 = arg2; + + /* + * Rule 1: Avoid unusable destinations. + * XXX: we currently do not consider if an appropriate route exists. + */ + if (dst1->aio_srcsa.sa_family != AF_UNSPEC && + dst2->aio_srcsa.sa_family == AF_UNSPEC) { + return(-1); + } + if (dst1->aio_srcsa.sa_family == AF_UNSPEC && + dst2->aio_srcsa.sa_family != AF_UNSPEC) { + return(1); + } + + /* Rule 2: Prefer matching scope. */ + if (dst1->aio_dstscope == dst1->aio_srcscope && + dst2->aio_dstscope != dst2->aio_srcscope) { + return(-1); + } + if (dst1->aio_dstscope != dst1->aio_srcscope && + dst2->aio_dstscope == dst2->aio_srcscope) { + return(1); + } + + /* Rule 3: Avoid deprecated addresses. */ + if (dst1->aio_srcsa.sa_family != AF_UNSPEC && + dst2->aio_srcsa.sa_family != AF_UNSPEC) { + if (!(dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) && + (dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) { + return(-1); + } + if ((dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) && + !(dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) { + return(1); + } + } + + /* Rule 4: Prefer home addresses. */ + /* XXX: not implemented yet */ + + /* Rule 5: Prefer matching label. */ +#ifdef INET6 + if (dst1->aio_srcpolicy && dst1->aio_dstpolicy && + dst1->aio_srcpolicy->pc_policy.label == + dst1->aio_dstpolicy->pc_policy.label && + (dst2->aio_srcpolicy == NULL || dst2->aio_dstpolicy == NULL || + dst2->aio_srcpolicy->pc_policy.label != + dst2->aio_dstpolicy->pc_policy.label)) { + return(-1); + } + if (dst2->aio_srcpolicy && dst2->aio_dstpolicy && + dst2->aio_srcpolicy->pc_policy.label == + dst2->aio_dstpolicy->pc_policy.label && + (dst1->aio_srcpolicy == NULL || dst1->aio_dstpolicy == NULL || + dst1->aio_srcpolicy->pc_policy.label != + dst1->aio_dstpolicy->pc_policy.label)) { + return(1); + } +#endif + + /* Rule 6: Prefer higher precedence. */ +#ifdef INET6 + if (dst1->aio_dstpolicy && + (dst2->aio_dstpolicy == NULL || + dst1->aio_dstpolicy->pc_policy.preced > + dst2->aio_dstpolicy->pc_policy.preced)) { + return(-1); + } + if (dst2->aio_dstpolicy && + (dst1->aio_dstpolicy == NULL || + dst2->aio_dstpolicy->pc_policy.preced > + dst1->aio_dstpolicy->pc_policy.preced)) { + return(1); + } +#endif + + /* Rule 7: Prefer native transport. */ + /* XXX: not implemented yet */ + + /* Rule 8: Prefer smaller scope. */ + if (dst1->aio_dstscope >= 0 && + dst1->aio_dstscope < dst2->aio_dstscope) { + return(-1); + } + if (dst2->aio_dstscope >= 0 && + dst2->aio_dstscope < dst1->aio_dstscope) { + return(1); + } + + /* + * Rule 9: Use longest matching prefix. + * We compare the match length in a same AF only. + */ + if (dst1->aio_sa.sa_family == dst2->aio_sa.sa_family) { + if (dst1->aio_matchlen > dst2->aio_matchlen) { + return(-1); + } + if (dst1->aio_matchlen < dst2->aio_matchlen) { + return(1); + } + } + + /* Rule 10: Otherwise, leave the order unchanged. */ + return(-1); +} + +/* + * Copy from scope.c. + * XXX: we should standardize the functions and link them as standard + * library. + */ +static int +gai_addr2scopetype(sa) + struct sockaddr *sa; +{ +#ifdef INET6 + struct sockaddr_in6 *sa6; +#endif + struct sockaddr_in *sa4; + + switch(sa->sa_family) { +#ifdef INET6 + case AF_INET6: + sa6 = (struct sockaddr_in6 *)sa; + if (IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) { + /* just use the scope field of the multicast address */ + return(sa6->sin6_addr.s6_addr[2] & 0x0f); + } + /* + * Unicast addresses: map scope type to corresponding scope + * value defined for multcast addresses. + * XXX: hardcoded scope type values are bad... + */ + if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr)) + return(1); /* node local scope */ + if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr)) + return(2); /* link-local scope */ + if (IN6_IS_ADDR_SITELOCAL(&sa6->sin6_addr)) + return(5); /* site-local scope */ + return(14); /* global scope */ + break; +#endif + case AF_INET: + /* + * IPv4 pseudo scoping according to RFC 3484. + */ + sa4 = (struct sockaddr_in *)sa; + /* IPv4 autoconfiguration addresses have link-local scope. */ + if (((u_char *)&sa4->sin_addr)[0] == 169 && + ((u_char *)&sa4->sin_addr)[1] == 254) + return(2); + /* Private addresses have site-local scope. */ + if (((u_char *)&sa4->sin_addr)[0] == 10 || + (((u_char *)&sa4->sin_addr)[0] == 172 && + (((u_char *)&sa4->sin_addr)[1] & 0xf0) == 16) || + (((u_char *)&sa4->sin_addr)[0] == 192 && + ((u_char *)&sa4->sin_addr)[1] == 168)) + return(14); /* XXX: It should be 5 unless NAT */ + /* Loopback addresses have link-local scope. */ + if (((u_char *)&sa4->sin_addr)[0] == 127) + return(2); + return(14); + break; + default: + errno = EAFNOSUPPORT; /* is this a good error? */ + return(-1); + } +} + /* * FILES (/etc/hosts) */ -- cgit v1.1