diff options
| -rw-r--r-- | common/socket.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/common/socket.c b/common/socket.c index 4d3956c..86cbf48 100644 --- a/common/socket.c +++ b/common/socket.c @@ -43,6 +43,10 @@ static int wsa_init = 0; #include <netdb.h> #include <arpa/inet.h> #include <fcntl.h> +#ifdef AF_INET6 +#include <net/if.h> +#include <ifaddrs.h> +#endif #endif #include "socket.h" @@ -342,6 +346,115 @@ int socket_create(const char* addr, uint16_t port) return sfd; } +#ifdef AF_INET6 +static uint32_t _in6_addr_scope(struct in6_addr* addr) +{ + uint32_t scope = 0; + + if (IN6_IS_ADDR_MULTICAST(addr)) { + if (IN6_IS_ADDR_MC_NODELOCAL(addr)) { + scope = 1; + } else if (IN6_IS_ADDR_MC_LINKLOCAL(addr)) { + scope = 2; + } else if (IN6_IS_ADDR_MC_SITELOCAL(addr)) { + scope = 5; + } + + return scope; + } + + if (IN6_IS_ADDR_LINKLOCAL(addr)) { + scope = 2; + } else if (IN6_IS_ADDR_LOOPBACK(addr)) { + scope = 2; + } else if (IN6_IS_ADDR_SITELOCAL(addr)) { + scope = 5; + } else if (IN6_IS_ADDR_UNSPECIFIED(addr)) { + scope = 0; + } + + return scope; +} + +static int32_t _sockaddr_in6_scope_id(struct sockaddr_in6* addr) +{ + int32_t res = -1; + struct ifaddrs *ifaddr, *ifa; + uint32_t addr_scope; + + /* get scope for requested address */ + addr_scope = _in6_addr_scope(&addr->sin6_addr); + if (addr_scope == 0) { + /* global scope doesn't need a specific scope id */ + return addr_scope; + } + + /* get interfaces */ + if (getifaddrs(&ifaddr) == -1) { + perror("getifaddrs"); + return res; + } + + /* loop over interfaces */ + for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) { + /* skip if no address is available */ + if (ifa->ifa_addr == NULL) { + continue; + } + + /* skip if wrong family */ + if (ifa->ifa_addr->sa_family != AF_INET6) { + continue; + } + + /* skip if not up */ + if ((ifa->ifa_flags & IFF_UP) == 0) { + continue; + } + + /* skip if not running */ + if ((ifa->ifa_flags & IFF_RUNNING) == 0) { + continue; + } + + struct sockaddr_in6* addr_in = (struct sockaddr_in6*)ifa->ifa_addr; + + /* skip if scopes do not match */ + if (_in6_addr_scope(&addr_in->sin6_addr) != addr_scope) { + continue; + } + + /* use if address is equal */ + if (memcmp(&addr->sin6_addr.s6_addr, &addr_in->sin6_addr.s6_addr, sizeof(addr_in->sin6_addr.s6_addr)) == 0) { + res = addr_in->sin6_scope_id; + /* if scope id equals the requested one then assume it was valid */ + if (addr->sin6_scope_id == addr_in->sin6_scope_id) { + break; + } else { + continue; + } + } + + /* skip loopback interface if not already matched exactly above */ + if ((ifa->ifa_flags & IFF_LOOPBACK) != 0) { + continue; + } + + /* set the scope id of this interface as most likely candidate */ + res = addr_in->sin6_scope_id; + + /* if scope id equals the requested one then assume it was valid */ + if (addr->sin6_scope_id == addr_in->sin6_scope_id) { + break; + } + } + + freeifaddrs(ifaddr); + + return res; +} +#endif + int socket_connect_addr(struct sockaddr* addr, uint16_t port) { int sfd = -1; @@ -369,6 +482,18 @@ int socket_connect_addr(struct sockaddr* addr, uint16_t port) else if (addr->sa_family == AF_INET6) { struct sockaddr_in6* addr_in = (struct sockaddr_in6*)addr; addr_in->sin6_port = htons(port); + + /* + * IPv6 Routing Magic: + * + * If the scope of the address is a link-local one, IPv6 requires the + * scope id set to an interface number to allow proper routing. However, + * as the provided sockaddr might contain a wrong scope id, we must find + * a scope id from a suitable interface on this system or routing might + * fail. An IPv6 guru should have another look though... + */ + addr_in->sin6_scope_id = _sockaddr_in6_scope_id(addr_in); + addrlen = sizeof(struct sockaddr_in6); } #endif |