| 1 | /* -*- indent-tabs-mode: nil; -*- */
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| 2 | #include "proxy.h"
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| 3 |
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| 4 | #include <sys/types.h>
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| 5 | #include <sys/socket.h>
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| 6 |
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| 7 | #include <net/if_dl.h>
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| 8 | #include <net/route.h>
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| 9 |
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| 10 | #include <netinet/in.h>
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| 11 | #include <netinet/ip6.h>
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| 12 |
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| 13 | #include <errno.h>
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| 14 | #include <string.h>
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| 15 | #include <unistd.h>
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| 16 |
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| 17 |
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| 18 | /**
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| 19 | * Query IPv6 routing table - BSD routing sockets version.
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| 20 | *
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| 21 | * We don't actually monitor the routing socket for updates, and
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| 22 | * instead query the kernel each time.
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| 23 | *
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| 24 | * We take a shortcut and don't read the reply to our RTM_GET - if
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| 25 | * there's no default IPv6 route, write(2) will fail with ESRCH
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| 26 | * synchronously. In theory it may fail asynchronously and we should
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| 27 | * wait for the RTM_GET reply and check rt_msghdr::rtm_errno.
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| 28 | *
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| 29 | * KAME code in *BSD maintains internally a list of default routers
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| 30 | * that it learned from RAs, and installs only one of them into the
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| 31 | * routing table (actually, I'm not sure if BSD routing table can
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| 32 | * handle multiple routes to the same destination). One side-effect
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| 33 | * of this is that when manually configured route (e.g. teredo) is
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| 34 | * deleted, the system will lose its default route even when KAME IPv6
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| 35 | * has default router(s) in its internal list. Next RA will force the
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| 36 | * update, though.
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| 37 | *
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| 38 | * Solaris does expose multiple routes in the routing table and
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| 39 | * replies to RTM_GET with "default default".
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| 40 | */
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| 41 | int
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| 42 | rtmon_get_defaults(void)
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| 43 | {
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| 44 | int rtsock;
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| 45 | struct req {
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| 46 | struct rt_msghdr rtm;
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| 47 | struct sockaddr_in6 dst;
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| 48 | struct sockaddr_in6 mask;
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| 49 | struct sockaddr_dl ifp;
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| 50 | } req;
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| 51 | ssize_t nsent;
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| 52 |
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| 53 | rtsock = socket(PF_ROUTE, SOCK_RAW, AF_INET6);
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| 54 | if (rtsock < 0) {
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| 55 | DPRINTF0(("rtmon: failed to create routing socket\n"));
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| 56 | return -1;
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| 57 | }
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| 58 |
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| 59 | memset(&req, 0, sizeof(req));
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| 60 |
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| 61 | req.rtm.rtm_type = RTM_GET;
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| 62 | req.rtm.rtm_version = RTM_VERSION;
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| 63 | req.rtm.rtm_msglen = sizeof(req);
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| 64 | req.rtm.rtm_seq = 0x12345;
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| 65 |
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| 66 | req.rtm.rtm_flags = RTF_UP;
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| 67 | req.rtm.rtm_addrs = RTA_DST | RTA_NETMASK | RTA_IFP;
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| 68 |
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| 69 | req.dst.sin6_family = AF_INET6;
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| 70 | #if HAVE_SA_LEN
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| 71 | req.dst.sin6_len = sizeof(req.dst);
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| 72 | #endif
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| 73 |
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| 74 | req.mask.sin6_family = AF_INET6;
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| 75 | #if HAVE_SA_LEN
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| 76 | req.mask.sin6_len = sizeof(req.mask);
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| 77 | #endif
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| 78 |
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| 79 | req.ifp.sdl_family = AF_LINK;
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| 80 | #if HAVE_SA_LEN
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| 81 | req.ifp.sdl_len = sizeof(req.ifp);
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| 82 | #endif
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| 83 |
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| 84 | nsent = write(rtsock, &req, req.rtm.rtm_msglen);
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| 85 | if (nsent < 0) {
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| 86 | if (errno == ESRCH) {
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| 87 | /* there's no default route */
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| 88 | return 0;
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| 89 | }
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| 90 | else {
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| 91 | DPRINTF0(("rtmon: failed to send RTM_GET\n"));
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| 92 | return -1;
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| 93 | }
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| 94 | }
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| 95 |
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| 96 | return 1;
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| 97 | }
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