From: Matthias Schiffer Date: Fri, 10 Jan 2014 16:38:39 +0000 (+0100) Subject: Use getifaddrs to get the interface-id when not specified X-Git-Tag: debian/1.1+git20160131-1~102^2~1 X-Git-Url: https://git.decadent.org.uk/gitweb/?a=commitdiff_plain;h=f32139023a83bf2bb3713d1a447ed042c36c9e3c;p=odhcp6c.git Use getifaddrs to get the interface-id when not specified Reimplementing this section also fixes two potential bugs: 1. Only link-local addresses should be used for automatic interface-id selection, as it should always be assigned by the kernel and is always based on the EUI-64 unless an administrator is doing strange things (while other addresses might be chosen according to the privacy extensions or by an administrator) 2. When no address is available (because of a race condition or because an administrator removed it), RA packets should just be ignored; otherwise an address with a zero interface-id might be assigned --- diff --git a/src/ra.c b/src/ra.c index ceded54..d048e85 100644 --- a/src/ra.c +++ b/src/ra.c @@ -13,6 +13,7 @@ */ #include +#include #include #include #include @@ -24,6 +25,7 @@ #include #include #include +#include #include #include @@ -225,23 +227,36 @@ bool ra_process(void) { bool found = false; bool changed = false; + bool has_lladdr = !IN6_IS_ADDR_UNSPECIFIED(&lladdr); uint8_t buf[1500], cmsg_buf[128]; struct nd_router_advert *adv = (struct nd_router_advert*)buf; struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0}; const struct in6_addr any = IN6ADDR_ANY_INIT; - if (IN6_IS_ADDR_UNSPECIFIED(&lladdr)) { + if (!has_lladdr) { // Autodetect interface-id if not specified - FILE *fp = fopen("/proc/net/if_inet6", "r"); - if (fp) { - char addrbuf[33], ifbuf[16]; - while (fscanf(fp, "%32s %*x %*x %*x %*x %15s", addrbuf, ifbuf) == 2) { - if (!strcmp(ifbuf, if_name)) { - script_unhexlify((uint8_t*)&lladdr, sizeof(lladdr), addrbuf); + struct ifaddrs *ifaddr, *ifa; + + if (getifaddrs(&ifaddr) == 0) { + for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) { + struct sockaddr_in6 *addr; + + if (ifa->ifa_addr == NULL || ifa->ifa_addr->sa_family != AF_INET6) + continue; + + addr = (struct sockaddr_in6*)ifa->ifa_addr; + + if (!IN6_IS_ADDR_LINKLOCAL(&addr->sin6_addr)) + continue; + + if (!strcmp(ifa->ifa_name, if_name)) { + lladdr = addr->sin6_addr; + has_lladdr = true; break; } } - fclose(fp); + + freeifaddrs(ifaddr); } } @@ -255,6 +270,9 @@ bool ra_process(void) if (len <= 0) break; + if (!has_lladdr) + continue; + int hlim = 0; for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; ch = CMSG_NXTHDR(&msg, ch))