diff options
| -rw-r--r-- | ggsn/ggsn.c | 5 | ||||
| -rw-r--r-- | lib/icmpv6.c | 111 | ||||
| -rw-r--r-- | lib/icmpv6.h | 81 | ||||
| -rw-r--r-- | lib/netdev.c | 65 | ||||
| -rw-r--r-- | lib/netdev.h | 2 | ||||
| -rw-r--r-- | sgsnemu/sgsnemu.c | 161 |
6 files changed, 307 insertions, 118 deletions
diff --git a/ggsn/ggsn.c b/ggsn/ggsn.c index 3b10f70..159362f 100644 --- a/ggsn/ggsn.c +++ b/ggsn/ggsn.c @@ -636,11 +636,6 @@ static int cb_tun_ind(struct tun_t *tun, void *pack, unsigned len) return 0; } -/* RFC3307 link-local scope multicast address */ -static const struct in6_addr all_router_mcast_addr = { - .s6_addr = { 0xff,0x02,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,2 } -}; - /* MS-originated GTP1-U packet, needs to be sent via TUN device */ static int encaps_tun(struct pdp_t *pdp, void *pack, unsigned len) { diff --git a/lib/icmpv6.c b/lib/icmpv6.c index ae72b4c..1bddf65 100644 --- a/lib/icmpv6.c +++ b/lib/icmpv6.c @@ -27,6 +27,7 @@ #include "../gtp/pdp.h" #include "ippool.h" #include "syserr.h" +#include "icmpv6.h" #include "config.h" /* 29.061 11.2.1.3.4 IPv6 Router Configuration Variables in GGSN */ @@ -35,61 +36,11 @@ #define GGSN_AdvValidLifetime 0xffffffff /* infinite */ #define GGSN_AdvPreferredLifetime 0xffffffff /* infinite */ -struct icmpv6_hdr { - uint8_t type; - uint8_t code; - uint16_t csum; -} __attribute__ ((packed)); - -/* RFC4861 Section 4.2 */ -struct icmpv6_radv_hdr { - struct icmpv6_hdr hdr; - uint8_t cur_ho_limit; -#if BYTE_ORDER == LITTLE_ENDIAN - uint8_t res:6, - m:1, - o:1; -#elif BYTE_ORDER == BIG_ENDIAN - uint8_t m:1, - o:1, - res:6; -#else -# error "Please fix <bits/endian.h>" -#endif - uint16_t router_lifetime; - uint32_t reachable_time; - uint32_t retrans_timer; - uint8_t options[0]; -} __attribute__ ((packed)); - -/* RFC4861 Section 4.6 */ -struct icmpv6_opt_hdr { - uint8_t type; - /* length in units of 8 octets, including type+len! */ - uint8_t len; - uint8_t data[0]; -} __attribute__ ((packed)); - -/* RFC4861 Section 4.6.2 */ -struct icmpv6_opt_prefix { - struct icmpv6_opt_hdr hdr; - uint8_t prefix_len; -#if BYTE_ORDER == LITTLE_ENDIAN - uint8_t res:6, - a:1, - l:1; -#elif BYTE_ORDER == BIG_ENDIAN - uint8_t l:1, - a:1, - res:6; -#else -# error "Please fix <bits/endian.h>" -#endif - uint32_t valid_lifetime; - uint32_t preferred_lifetime; - uint32_t res2; - uint8_t prefix[16]; -} __attribute__ ((packed)); +/* RFC3307 link-local scope multicast address */ +const struct in6_addr all_router_mcast_addr = { + .s6_addr = { 0xff,0x02,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,2 } +}; + /* Prepends the ipv6 header and returns checksum content */ static uint16_t icmpv6_prepend_ip6hdr(struct msgb *msg, const struct in6_addr *saddr, const struct in6_addr *daddr) @@ -115,7 +66,26 @@ static uint16_t icmpv6_prepend_ip6hdr(struct msgb *msg, const struct in6_addr *s return skb_csum; } +/*! construct a RFC4861 compliant ICMPv6 router soliciation + * \param[in] saddr Source IPv6 address for router advertisement + * \param[in] daddr Destination IPv6 address for router advertisement IPv6 header + * \param[in] prefix The single prefix to be advertised (/64 implied!) + * \returns callee-allocated message buffer containing router advertisement */ +struct msgb *icmpv6_construct_rs(const struct in6_addr *saddr) +{ + struct msgb *msg = msgb_alloc_headroom(512,128, "IPv6 RS"); + struct icmpv6_rsol_hdr *rs; + OSMO_ASSERT(msg); + rs = (struct icmpv6_rsol_hdr *) msgb_put(msg, sizeof(*rs)); + rs->hdr.type = 133; /* see RFC4861 4.1 */ + rs->hdr.code = 0; /* see RFC4861 4.1 */ + rs->hdr.csum = 0; /* updated below */ + rs->reserved = 0; /* see RFC4861 4.1 */ + + rs->hdr.csum = icmpv6_prepend_ip6hdr(msg, saddr, &all_router_mcast_addr); + return msg; +} /*! construct a 3GPP 29.061 compliant router advertisement for a given prefix * \param[in] saddr Source IPv6 address for router advertisement * \param[in] daddr Destination IPv6 address for router advertisement IPv6 header @@ -188,6 +158,37 @@ static bool icmpv6_validate_router_solicit(const uint8_t *pack, unsigned len) return true; } +/* Validate an ICMPv6 router advertisement according to RFC4861 6.1.2. + Returns pointer packet header on success, NULL otherwise. */ +struct icmpv6_radv_hdr *icmpv6_validate_router_adv(const uint8_t *pack, unsigned len) +{ + const struct ip6_hdr *ip6h = (struct ip6_hdr *)pack; + const struct icmpv6_hdr *ic6h = (struct icmpv6_hdr *) (pack + sizeof(*ip6h)); + + /* ICMP length (derived from IP length) is 16 or more octets */ + if (len < sizeof(*ip6h) + 16) + return NULL; + + if (ic6h->type != 134) /* router advertismenet type */ + return NULL; + + /*Routers must use their link-local address */ + if (!IN6_IS_ADDR_LINKLOCAL(&ip6h->ip6_src)) + return NULL; + /* Hop limit field must have 255 */ + if (ip6h->ip6_ctlun.ip6_un1.ip6_un1_hlim != 255) + return NULL; + /* ICMP Code is 0 */ + if (ic6h->code != 0) + return NULL; + /* ICMP length (derived from IP length) is 16 or more octets */ + if (ip6h->ip6_ctlun.ip6_un1.ip6_un1_plen < 16) + return NULL; + /* FIXME: All included options have a length > 0 */ + /* FIXME: If IP source is unspecified, no source link-layer addr option */ + return (struct icmpv6_radv_hdr *)ic6h; +} + /* handle incoming packets to the all-routers multicast address */ int handle_router_mcast(struct gsn_t *gsn, struct pdp_t *pdp, const struct in6_addr *pdp_prefix, diff --git a/lib/icmpv6.h b/lib/icmpv6.h index bf91e27..44b9b73 100644 --- a/lib/icmpv6.h +++ b/lib/icmpv6.h @@ -1,9 +1,90 @@ #pragma once +#include <stdbool.h> + +#include <osmocom/core/msgb.h> +#include <osmocom/core/endian.h> + #include "../gtp/gtp.h" #include "../gtp/pdp.h" +#define ICMPv6_OPT_TYPE_PREFIX_INFO 0x03 + +#define foreach_icmpv6_opt(icmpv6_pkt, icmpv6_len, opt_hdr) \ + for (opt_hdr = (struct icmpv6_opt_hdr *)(icmpv6_pkt)->options; \ + (uint8_t*)(opt_hdr) + sizeof(struct icmpv6_opt_hdr) <= (((uint8_t*)(icmpv6_pkt)) + (icmpv6_len)); \ + opt_hdr = (struct icmpv6_opt_hdr*)((uint8_t*)(opt_hdr) + (opt_hdr)->len) \ + ) + +struct icmpv6_hdr { + uint8_t type; + uint8_t code; + uint16_t csum; +} __attribute__ ((packed)); + +/* RFC4861 Section 4.1 */ +struct icmpv6_rsol_hdr { + struct icmpv6_hdr hdr; + uint32_t reserved; + uint8_t options[0]; +} __attribute__ ((packed)); + +/* RFC4861 Section 4.2 */ +struct icmpv6_radv_hdr { + struct icmpv6_hdr hdr; + uint8_t cur_ho_limit; +#if OSMO_IS_LITTLE_ENDIAN + uint8_t res:6, + m:1, + o:1; +#else + uint8_t m:1, + o:1, + res:6; +#endif + uint16_t router_lifetime; + uint32_t reachable_time; + uint32_t retrans_timer; + uint8_t options[0]; +} __attribute__ ((packed)); + + +/* RFC4861 Section 4.6 */ +struct icmpv6_opt_hdr { + uint8_t type; + /* length in units of 8 octets, including type+len! */ + uint8_t len; + uint8_t data[0]; +} __attribute__ ((packed)); + +/* RFC4861 Section 4.6.2 */ +struct icmpv6_opt_prefix { + struct icmpv6_opt_hdr hdr; + uint8_t prefix_len; +#if OSMO_IS_LITTLE_ENDIAN + uint8_t res:6, + a:1, + l:1; +#else + uint8_t l:1, + a:1, + res:6; +#endif + uint32_t valid_lifetime; + uint32_t preferred_lifetime; + uint32_t res2; + uint8_t prefix[16]; +} __attribute__ ((packed)); + +struct msgb *icmpv6_construct_rs(const struct in6_addr *saddr); + int handle_router_mcast(struct gsn_t *gsn, struct pdp_t *pdp, const struct in6_addr *pdp_prefix, const struct in6_addr *own_ll_addr, const uint8_t *pack, unsigned len); + +struct icmpv6_radv_hdr *icmpv6_validate_router_adv(const uint8_t *pack, unsigned len); + + +/* RFC3307 link-local scope multicast address */ +extern const struct in6_addr all_router_mcast_addr; diff --git a/lib/netdev.c b/lib/netdev.c index 4d171c9..fd3caff 100644 --- a/lib/netdev.c +++ b/lib/netdev.c @@ -643,6 +643,59 @@ static int netdev_route4(struct in_addr *dst, struct in_addr *gateway, struct in return 0; } +static int netdev_route6(struct in6_addr *dst, struct in6_addr *gateway, int prefixlen, const char *gw_iface, int delete) +{ + int fd; +#if defined(__linux__) + struct in6_rtmsg r; + struct ifreq ifr; + + memset(&r, 0, sizeof(r)); + r.rtmsg_flags = RTF_UP | RTF_GATEWAY; /* RTF_HOST not set */ + r.rtmsg_metric = 1; + + /* Create a channel to the NET kernel. */ + if ((fd = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) { + SYS_ERR(DTUN, LOGL_ERROR, errno, "socket() failed"); + return -1; + } + + if (gw_iface) { + strncpy(ifr.ifr_name, gw_iface, IFNAMSIZ); + ifr.ifr_name[IFNAMSIZ - 1] = 0; /* Make sure to terminate */ + if (ioctl(fd, SIOCGIFINDEX, &ifr) < 0) { + SYS_ERR(DTUN, LOGL_ERROR, errno, + "ioctl(SIOCGIFINDEX) failed"); + close(fd); + return -1; + } + r.rtmsg_ifindex = ifr.ifr_ifindex; + } + + memcpy(&r.rtmsg_dst, dst->s6_addr, sizeof(struct in6_addr)); + memcpy(&r.rtmsg_gateway, gateway->s6_addr, sizeof(struct in6_addr)); + r.rtmsg_dst_len = prefixlen; + + if (delete) { + if (ioctl(fd, SIOCDELRT, (void *)&r) < 0) { + SYS_ERR(DTUN, LOGL_ERROR, errno, + "ioctl(SIOCDELRT) failed"); + close(fd); + return -1; + } + } else { + if (ioctl(fd, SIOCADDRT, (void *)&r) < 0) { + SYS_ERR(DTUN, LOGL_ERROR, errno, + "ioctl(SIOCADDRT) failed"); + close(fd); + return -1; + } + } + close(fd); +#endif + return 0; +} + int netdev_addroute4(struct in_addr *dst, struct in_addr *gateway, struct in_addr *mask) { return netdev_route4(dst, gateway, mask, 0); @@ -653,6 +706,18 @@ int netdev_delroute4(struct in_addr *dst, struct in_addr *gateway, struct in_add return netdev_route4(dst, gateway, mask, 1); } +int netdev_addroute6(struct in6_addr *dst, struct in6_addr *gateway, int prefixlen, const char *gw_iface) +{ + return netdev_route6(dst, gateway, prefixlen, gw_iface, 0); +} + +int netdev_delroute6(struct in6_addr *dst, struct in6_addr *gateway, int prefixlen, const char *gw_iface) +{ + return netdev_route6(dst, gateway, prefixlen, gw_iface, 1); +} + + + #include <ifaddrs.h> /*! Obtain the local address of a network device diff --git a/lib/netdev.h b/lib/netdev.h index 5dab27f..1bce814 100644 --- a/lib/netdev.h +++ b/lib/netdev.h @@ -67,6 +67,8 @@ extern int netdev_addaddr6(const char *devname, struct in6_addr *addr, extern int netdev_addroute4(struct in_addr *dst, struct in_addr *gateway, struct in_addr *mask); extern int netdev_delroute4(struct in_addr *dst, struct in_addr *gateway, struct in_addr *mask); +extern int netdev_addroute6(struct in6_addr *dst, struct in6_addr *gateway, int prefixlen, const char *gw_iface); +extern int netdev_delroute6(struct in6_addr *dst, struct in6_addr *gateway, int prefixlen, const char *gw_iface); extern int netdev_ip_local_get(const char *devname, struct in46_prefix *prefix_list, size_t prefix_size, int flags); diff --git a/sgsnemu/sgsnemu.c b/sgsnemu/sgsnemu.c index ea52da6..69879dd 100644 --- a/sgsnemu/sgsnemu.c +++ b/sgsnemu/sgsnemu.c @@ -58,6 +58,7 @@ #include "../lib/ippool.h" #include "../lib/syserr.h" #include "../lib/netns.h" +#include "../lib/icmpv6.h" #include "../gtp/pdp.h" #include "../gtp/gtp.h" #include "cmdline.h" @@ -966,41 +967,6 @@ static int process_options(int argc, char **argv) } -/* read a single value from a /procc file, up to 255 bytes, callee-allocated */ -static char *proc_read(const char *path) -{ - char *ret = NULL; - FILE *f; - - f = fopen(path, "r"); - if (!f) - return NULL; - - ret = malloc(256); - if (!ret) - goto out; - - if (!fgets(ret, 256, f)) { - free(ret); - ret = NULL; - goto out; - } - -out: - fclose(f); - return ret; -} - -/* Read value of a /proc/sys/net/ipv6/conf file for given device. - * Memory is dynamically allocated, caller must free it later. */ -static char *proc_ipv6_conf_read(const char *dev, const char *file) -{ - const char *fmt = "/proc/sys/net/ipv6/conf/%s/%s"; - char path[strlen(fmt) + strlen(dev) + strlen(file)+1]; - snprintf(path, sizeof(path), fmt, dev, file); - return proc_read(path); -} - /* write a single value to a /proc file */ static int proc_write(const char *path, const char *value) { @@ -1522,8 +1488,10 @@ static int create_pdp_conf(struct pdp_t *pdp, void *cbp, int cause) if (in46a_is_v4(&addr[i])) { struct in_addr rm; rm.s_addr = 0; - netdev_addroute4(&rm, &addr[i].v4, &rm); - } + if (netdev_addroute4(&rm, &addr[i].v4, &rm) < 0) { + SYS_ERR(DSGSN, LOGL_ERROR, 0, "Failed adding default route to %s", in46a_ntoa(&addr[i])); + } + } /* else: route will be set up once we have a global link address (Router Advertisement) */ } if (options.ipup) tun_runscript(tun, options.ipup); @@ -1532,29 +1500,21 @@ static int create_pdp_conf(struct pdp_t *pdp, void *cbp, int cause) ipset(iph, &addr[i]); } - /* now that ip-up has been executed, check if we are configured to - * accept router advertisements */ if (options.createif && options.pdp_type == PDP_EUA_TYPE_v6) { - char *accept_ra, *forwarding; - - accept_ra = proc_ipv6_conf_read(tun->devname, "accept_ra"); - forwarding = proc_ipv6_conf_read(tun->devname, "forwarding"); - if (!accept_ra || !forwarding) - printf("Could not open proc file for %s ?!?\n", tun->devname); - else { - if (!strcmp(accept_ra, "0")) { - printf("accept_ra=0, i.e. your tun device is not configured to accept " - "router advertisements; SLAAC will not succeed, please " - "fix your setup!\n"); - } - if (!strcmp(forwarding, "1") && !strcmp(accept_ra, "1")) { - printf("forwarding=1 and accept_ra=1, i.e. your tun device is not " - "configured to accept router advertisements; SLAAC will not " - "succeed, please fix your setup!\n"); - } + struct in6_addr *saddr6; + struct msgb *msg; + if (in46a_is_v6(&addr[0])) { + saddr6 = &addr[0].v6; + } else if (num_addr > 1 && in46a_is_v6(&addr[1])) { + saddr6 = &addr[1].v6; + } else { + SYS_ERR(DSGSN, LOGL_ERROR, 0, "Failed to find IPv6 EUA on IPv6 APN"); + return EOF; /* Not a valid IP address */ } - free(accept_ra); - free(forwarding); + SYS_ERR(DSGSN, LOGL_INFO, 0, "Sending ICMPv6 Router Soliciation to GGSN..."); + msg = icmpv6_construct_rs(saddr6); + gtp_data_req(gsn, iph->pdp, msgb_data(msg), msgb_length(msg)); + msgb_free(msg); } #if defined(__linux__) @@ -1618,8 +1578,83 @@ static int _gtp_cb_conf(int type, int cause, struct pdp_t *pdp, void *cbp) } } +static void handle_router_adv(struct ip6_hdr *ip6h, struct icmpv6_radv_hdr *ra, size_t ra_len) +{ + struct icmpv6_opt_hdr *opt_hdr; + struct icmpv6_opt_prefix *opt_prefix; + int rc; + sigset_t oldmask; + struct in6_addr rm; + char ip6strbuf[200]; + memset(&rm, 0, sizeof(rm)); + + SYS_ERR(DSGSN, LOGL_INFO, 0, "Received ICMPv6 Router Advertisement"); + + foreach_icmpv6_opt(ra, ra_len, opt_hdr) { + if (opt_hdr->type == ICMPv6_OPT_TYPE_PREFIX_INFO) { + opt_prefix = (struct icmpv6_opt_prefix *)opt_hdr; + size_t prefix_len_bytes = (opt_prefix->prefix_len + 7)/8; + SYS_ERR(DSGSN, LOGL_INFO, 0, "Parsing OPT Prefix info (prefix_len=%u): %s", + opt_prefix->prefix_len, + osmo_hexdump((const unsigned char *)opt_prefix->prefix, prefix_len_bytes)); + if ((options.createif) && (!options.netaddr.len)) { + struct in46_addr addr; + addr.len = 16; + memcpy(addr.v6.s6_addr, opt_prefix->prefix, prefix_len_bytes); + memset(&addr.v6.s6_addr[prefix_len_bytes], 0, 16 - prefix_len_bytes); + addr.v6.s6_addr[15] = 0x02; + SYS_ERR(DSGSN, LOGL_INFO, 0, "Adding addr %s to tun %s", + in46a_ntoa(&addr), tun->devname); + +#if defined(__linux__) + if ((options.netns)) { + if ((rc = switch_ns(netns, &oldmask)) < 0) { + SYS_ERR(DSGSN, LOGL_ERROR, 0, + "Failed to switch to netns %s: %s", + options.netns, strerror(-rc)); + } + } +#endif + rc = tun_addaddr(tun, &addr, NULL, opt_prefix->prefix_len); + if (rc < 0) { + SYS_ERR(DSGSN, LOGL_ERROR, 0, "Failed to add addr %s to tun %s", + in46a_ntoa(&addr), tun->devname); + } + + struct in6_addr rm; + memset(&rm, 0, sizeof(rm)); + if (netdev_addroute6(&rm, &ip6h->ip6_src, 0, tun->devname) < 0) { + SYS_ERR(DSGSN, LOGL_ERROR, 0, "Failed adding default route to %s", inet_ntop(AF_INET6, &ip6h->ip6_src, ip6strbuf, sizeof(ip6strbuf))); + } + +#if defined(__linux__) + if ((options.netns)) { + if ((rc = restore_ns(&oldmask)) < 0) { + SYS_ERR(DSGSN, LOGL_ERROR, 0, + "Failed to switch to original netns: %s", + strerror(-rc)); + } + } +#endif + } + } + } +} + static int encaps_tun(struct pdp_t *pdp, void *pack, unsigned len) { + struct iphdr *iph = (struct iphdr *)pack; + struct icmpv6_radv_hdr *ra; + switch (iph->version) { + case 6: + if ((ra = icmpv6_validate_router_adv(pack, len))) { + size_t ra_len = (uint8_t*)ra - (uint8_t*)pack; + handle_router_adv((struct ip6_hdr *)pack, ra, ra_len); + return 0; + } + break; + } + /* printf("encaps_tun. Packet received: forwarding to tun\n"); */ return tun_encaps((struct tun_t *)pdp->ipif, pack, len); } @@ -1721,6 +1756,12 @@ int main(int argc, char **argv) tun_set_cb_ind(tun, cb_tun_ind); if (tun->fd > maxfd) maxfd = tun->fd; + + if (proc_ipv6_conf_write(options.tun_dev_name, "accept_ra", "0") < 0) { + SYS_ERR(DSGSN, LOGL_ERROR, 0, + "Failed to disable IPv6 SLAAC on %s\n", options.tun_dev_name); + exit(1); + } } if ((options.createif) && (options.netaddr.len)) { @@ -1730,6 +1771,10 @@ int main(int argc, char **argv) struct in_addr rm; rm.s_addr = 0; netdev_addroute4(&rm, &options.netaddr.v4, &rm); + } else { + struct in6_addr rm; + memset(&rm, 0, sizeof(rm)); + netdev_addroute6(&rm, &options.netaddr.v6, 0, tun->devname); } } if (options.ipup) |