137 lines
3.6 KiB
C
137 lines
3.6 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Copyright (C) 2011 Denys Vlasenko.
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*
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* Licensed under GPLv2, see file LICENSE in this source tree.
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*/
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#include "common.h"
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#include "d6_common.h"
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#include <net/if.h>
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#include <ifaddrs.h>
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#include <netpacket/packet.h>
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int FAST_FUNC d6_read_interface(
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const char *interface,
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int *ifindex,
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struct in6_addr *nip6,
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uint8_t *mac)
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{
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int retval = 3;
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struct ifaddrs *ifap, *ifa;
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getifaddrs(&ifap);
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for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
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struct sockaddr_in6 *sip6;
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if (!ifa->ifa_addr || (strcmp(ifa->ifa_name, interface) != 0))
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continue;
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if (ifa->ifa_addr->sa_family == AF_PACKET) {
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struct sockaddr_ll *sll = (void*)(ifa->ifa_addr);
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memcpy(mac, sll->sll_addr, 6);
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log2("MAC %02x:%02x:%02x:%02x:%02x:%02x",
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mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]
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);
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*ifindex = sll->sll_ifindex;
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log2("ifindex %d", *ifindex);
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retval &= (3 - (1<<0));
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}
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#if 0
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if (ifa->ifa_addr->sa_family == AF_INET) {
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*nip = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr.s_addr;
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log1("IP %s", inet_ntoa(((struct sockaddr_in *)ifa->ifa_addr)->sin_addr));
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}
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#endif
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/* RFC 3315
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* 16. Client Source Address and Interface Selection
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*
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* "When a client sends a DHCP message to the
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* All_DHCP_Relay_Agents_and_Servers address, ... ... The client
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* MUST use a link-local address assigned to the interface for which it
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* is requesting configuration information as the source address in the
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* header of the IP datagram."
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*/
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sip6 = (void*)(ifa->ifa_addr);
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if (ifa->ifa_addr->sa_family == AF_INET6
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&& IN6_IS_ADDR_LINKLOCAL(&sip6->sin6_addr)
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) {
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*nip6 = sip6->sin6_addr; /* struct copy */
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log1(
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"IPv6 %02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x",
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nip6->s6_addr[0], nip6->s6_addr[1],
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nip6->s6_addr[2], nip6->s6_addr[3],
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nip6->s6_addr[4], nip6->s6_addr[5],
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nip6->s6_addr[6], nip6->s6_addr[7],
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nip6->s6_addr[8], nip6->s6_addr[9],
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nip6->s6_addr[10], nip6->s6_addr[11],
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nip6->s6_addr[12], nip6->s6_addr[13],
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nip6->s6_addr[14], nip6->s6_addr[15]
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);
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retval &= (3 - (1<<1));
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}
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}
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freeifaddrs(ifap);
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if (retval & (1<<0)) {
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/* This iface has no MAC (e.g. ppp), generate a random one */
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struct ifreq ifr;
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int fd;
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/*memset(&ifr, 0, sizeof(ifr)); - SIOCGIFINDEX does not need to clear all */
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strncpy_IFNAMSIZ(ifr.ifr_name, interface);
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fd = xsocket(AF_INET6, SOCK_RAW, IPPROTO_RAW);
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if (ioctl(fd, SIOCGIFINDEX, &ifr) == 0) {
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*ifindex = ifr.ifr_ifindex;
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log2("ifindex %d", *ifindex);
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if (((uint32_t*)mac)[0] == 0) {
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/* invent a fictitious MAC (once) */
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((uint32_t*)mac)[0] = rand();
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((uint16_t*)mac)[2] = rand();
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mac[0] &= 0xfc; /* make sure it's not bcast */
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}
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retval &= (3 - (1<<0));
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}
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close(fd);
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}
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if (retval & (1<<0))
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bb_error_msg("can't get %s", "MAC");
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if (retval & (1<<1))
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bb_error_msg("can't get %s", "link-local IPv6 address");
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return retval;
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}
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int FAST_FUNC d6_listen_socket(int port, const char *inf)
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{
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int fd;
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struct sockaddr_in6 addr;
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char *colon;
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log2("opening listen socket on *:%d %s", port, inf);
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fd = xsocket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
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setsockopt_reuseaddr(fd);
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if (setsockopt_broadcast(fd) == -1)
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bb_simple_perror_msg_and_die("SO_BROADCAST");
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/* SO_BINDTODEVICE doesn't work on ethernet aliases (ethN:M) */
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colon = strrchr(inf, ':');
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if (colon)
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*colon = '\0';
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if (setsockopt_bindtodevice(fd, inf))
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xfunc_die(); /* warning is already printed */
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if (colon)
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*colon = ':';
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memset(&addr, 0, sizeof(addr));
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addr.sin6_family = AF_INET6;
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addr.sin6_port = htons(port);
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/* addr.sin6_addr is all-zeros */
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xbind(fd, (struct sockaddr *)&addr, sizeof(addr));
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return fd;
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}
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