| /* SPDX-License-Identifier: GPL-2.0 */ |
| #include <unistd.h> |
| #include <stdint.h> |
| #include <stdbool.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <stdio.h> |
| #include <errno.h> |
| #include <sys/types.h> |
| #include <sys/socket.h> |
| #include <sys/stat.h> |
| #include <fcntl.h> |
| #include <signal.h> |
| #include <netdb.h> |
| |
| #include <netinet/ip.h> |
| #include <netinet/ip6.h> |
| |
| #include <pthread.h> |
| |
| #include <linux/if.h> |
| #include <linux/if_tun.h> |
| #include <sys/ioctl.h> |
| |
| #include <netlink/socket.h> |
| #include <netlink/route/link.h> |
| |
| #include <osmocom/core/linuxlist.h> |
| #include <osmocom/core/talloc.h> |
| #include <osmocom/core/logging.h> |
| #include <osmocom/core/utils.h> |
| |
| #include "gtp.h" |
| #include "internal.h" |
| #include "netns.h" |
| |
| /*********************************************************************** |
| * TUN Device |
| ***********************************************************************/ |
| |
| #define LOGTUN(tun, lvl, fmt, args ...) \ |
| LOGP(DTUN, lvl, "%s: " fmt, (tun)->devname, ## args) |
| |
| /* extracted information from a packet */ |
| struct pkt_info { |
| struct sockaddr_storage saddr; |
| struct sockaddr_storage daddr; |
| uint8_t proto; |
| }; |
| |
| static int parse_pkt(struct pkt_info *out, const uint8_t *in, unsigned int in_len) |
| { |
| const struct iphdr *ip4 = (struct iphdr *) in; |
| const uint16_t *l4h = NULL; |
| |
| memset(out, 0, sizeof(*out)); |
| |
| if (ip4->version == 4) { |
| struct sockaddr_in *saddr4 = (struct sockaddr_in *) &out->saddr; |
| struct sockaddr_in *daddr4 = (struct sockaddr_in *) &out->daddr; |
| |
| if (in_len < sizeof(*ip4) || in_len < 4*ip4->ihl) |
| return -1; |
| |
| saddr4->sin_family = AF_INET; |
| saddr4->sin_addr.s_addr = ip4->saddr; |
| |
| daddr4->sin_family = AF_INET; |
| daddr4->sin_addr.s_addr = ip4->daddr; |
| |
| out->proto = ip4->protocol; |
| l4h = (const uint16_t *) (in + sizeof(*ip4)); |
| |
| switch (out->proto) { |
| case IPPROTO_TCP: |
| case IPPROTO_UDP: |
| case IPPROTO_DCCP: |
| case IPPROTO_SCTP: |
| case IPPROTO_UDPLITE: |
| saddr4->sin_port = ntohs(l4h[0]); |
| daddr4->sin_port = ntohs(l4h[1]); |
| break; |
| default: |
| break; |
| } |
| } else if (ip4->version == 6) { |
| const struct ip6_hdr *ip6 = (struct ip6_hdr *) in; |
| struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *) &out->saddr; |
| struct sockaddr_in6 *daddr6 = (struct sockaddr_in6 *) &out->daddr; |
| |
| if (in_len < sizeof(*ip6)) |
| return -1; |
| |
| saddr6->sin6_family = AF_INET6; |
| saddr6->sin6_addr = ip6->ip6_src; |
| |
| daddr6->sin6_family = AF_INET6; |
| daddr6->sin6_addr = ip6->ip6_dst; |
| |
| /* FIXME: ext hdr */ |
| out->proto = ip6->ip6_nxt; |
| l4h = (const uint16_t *) (in + sizeof(*ip6)); |
| |
| switch (out->proto) { |
| case IPPROTO_TCP: |
| case IPPROTO_UDP: |
| case IPPROTO_DCCP: |
| case IPPROTO_SCTP: |
| case IPPROTO_UDPLITE: |
| saddr6->sin6_port = ntohs(l4h[0]); |
| daddr6->sin6_port = ntohs(l4h[1]); |
| break; |
| default: |
| break; |
| } |
| } else |
| return -1; |
| |
| return 0; |
| } |
| |
| /* one thread for reading from each TUN device (TUN -> GTP encapsulation) */ |
| static void *tun_device_thread(void *arg) |
| { |
| struct tun_device *tun = (struct tun_device *)arg; |
| struct gtp_daemon *d = tun->d; |
| |
| uint8_t base_buffer[MAX_UDP_PACKET+sizeof(struct gtp1_header)]; |
| struct gtp1_header *gtph = (struct gtp1_header *)base_buffer; |
| uint8_t *buffer = base_buffer + sizeof(struct gtp1_header); |
| |
| struct sockaddr_storage daddr; |
| |
| /* initialize the fixed part of the GTP header */ |
| gtph->flags = 0x30; |
| gtph->type = GTP_TPDU; |
| |
| while (1) { |
| struct gtp_tunnel *t; |
| struct pkt_info pinfo; |
| int rc, nread, outfd; |
| |
| /* 1) read from tun */ |
| rc = read(tun->fd, buffer, MAX_UDP_PACKET); |
| if (rc < 0) { |
| LOGTUN(tun, LOGL_FATAL, "Error readingfrom tun device: %s\n", strerror(errno)); |
| exit(1); |
| } |
| nread = rc; |
| gtph->length = htons(nread); |
| |
| rc = parse_pkt(&pinfo, buffer, nread); |
| if (rc < 0) { |
| LOGTUN(tun, LOGL_NOTICE, "Error parsing IP packet: %s\n", |
| osmo_hexdump(buffer, nread)); |
| continue; |
| } |
| |
| if (pinfo.saddr.ss_family == AF_INET6 && pinfo.proto == IPPROTO_ICMPV6) { |
| /* 2) TODO: magic voodoo for IPv6 neighbor discovery */ |
| } |
| |
| /* 3) look-up tunnel based on source IP address (+ filter) */ |
| pthread_rwlock_rdlock(&d->rwlock); |
| t = _gtp_tunnel_find_eua(tun, (struct sockaddr *) &pinfo.saddr, pinfo.proto); |
| if (!t) { |
| char host[128]; |
| char port[8]; |
| pthread_rwlock_unlock(&d->rwlock); |
| getnameinfo((const struct sockaddr *)&pinfo.saddr, |
| sizeof(pinfo.saddr), host, sizeof(host), port, sizeof(port), |
| NI_NUMERICHOST | NI_NUMERICSERV); |
| LOGTUN(tun, LOGL_NOTICE, "No tunnel found for source address %s:%s\n", host, port); |
| continue; |
| } |
| outfd = t->gtp_ep->fd; |
| memcpy(&daddr, &t->remote_udp, sizeof(daddr)); |
| gtph->tid = htonl(t->tx_teid); |
| pthread_rwlock_unlock(&d->rwlock); |
| |
| /* 4) write to GTP/UDP socket */ |
| rc = sendto(outfd, base_buffer, nread+sizeof(*gtph), 0, |
| (struct sockaddr *)&daddr, sizeof(daddr)); |
| if (rc < 0) { |
| LOGTUN(tun, LOGL_FATAL, "Error Writing to UDP socket: %s\n", strerror(errno)); |
| exit(1); |
| } |
| } |
| } |
| |
| static int tun_open(int flags, const char *name) |
| { |
| struct ifreq ifr; |
| int fd, rc; |
| |
| fd = open("/dev/net/tun", O_RDWR); |
| if (fd < 0) { |
| LOGP(DTUN, LOGL_ERROR, "Cannot open /dev/net/tun: %s\n", strerror(errno)); |
| return fd; |
| } |
| |
| memset(&ifr, 0, sizeof(ifr)); |
| ifr.ifr_flags = IFF_TUN | IFF_NO_PI | flags; |
| if (name) { |
| /* if a TUN interface name was specified, put it in the structure; otherwise, |
| the kernel will try to allocate the "next" device of the specified type */ |
| strncpy(ifr.ifr_name, name, IFNAMSIZ); |
| } |
| |
| /* try to create the device */ |
| rc = ioctl(fd, TUNSETIFF, (void *) &ifr); |
| if (rc < 0) { |
| close(fd); |
| return rc; |
| } |
| |
| /* FIXME: read name back from device? */ |
| /* FIXME: SIOCSIFTXQLEN / SIOCSIFFLAGS */ |
| |
| return fd; |
| } |
| |
| static struct tun_device * |
| _tun_device_create(struct gtp_daemon *d, const char *devname, const char *netns_name) |
| { |
| struct rtnl_link *link; |
| struct tun_device *tun; |
| sigset_t oldmask; |
| int rc; |
| |
| tun = talloc_zero(d, struct tun_device); |
| if (!tun) |
| return NULL; |
| |
| tun->d = d; |
| tun->use_count = 1; |
| tun->devname = talloc_strdup(tun, devname); |
| |
| if (netns_name) { |
| tun->netns_name = talloc_strdup(tun, netns_name); |
| tun->netns_fd = get_nsfd(tun->netns_name); |
| if (tun->netns_fd < 0) { |
| LOGTUN(tun, LOGL_ERROR, "Cannot obtain netns file descriptor: %s\n", |
| strerror(errno)); |
| goto err_free; |
| } |
| } |
| |
| /* temporarily switch to specified namespace to create tun device */ |
| if (tun->netns_name) { |
| rc = switch_ns(tun->netns_fd, &oldmask); |
| if (rc < 0) { |
| LOGTUN(tun, LOGL_ERROR, "Cannot switch to netns '%s': %s\n", |
| tun->netns_name, strerror(errno)); |
| goto err_close_ns; |
| } |
| } |
| |
| tun->fd = tun_open(0, tun->devname); |
| if (tun->fd < 0) { |
| LOGTUN(tun, LOGL_ERROR, "Cannot open TUN device: %s\n", strerror(errno)); |
| goto err_restore_ns; |
| } |
| |
| tun->nl = nl_socket_alloc(); |
| if (!tun->nl || nl_connect(tun->nl, NETLINK_ROUTE) < 0) { |
| LOGTUN(tun, LOGL_ERROR, "Cannot create netlink socket in namespace '%s'\n", |
| tun->netns_name); |
| goto err_close; |
| } |
| |
| rc = rtnl_link_get_kernel(tun->nl, 0, tun->devname, &link); |
| if (rc < 0) { |
| LOGTUN(tun, LOGL_ERROR, "Cannot get ifindex for netif after create?!?\n"); |
| goto err_free_nl; |
| } |
| tun->ifindex = rtnl_link_get_ifindex(link); |
| rtnl_link_put(link); |
| |
| /* switch back to default namespace before creating new thread */ |
| if (tun->netns_name) |
| OSMO_ASSERT(restore_ns(&oldmask) == 0); |
| |
| /* bring the network device up */ |
| rc = netdev_set_link(tun->nl, tun->ifindex, true); |
| if (rc < 0) |
| LOGTUN(tun, LOGL_ERROR, "Cannot set interface to 'up'\n"); |
| |
| if (tun->netns_name) { |
| rc = netdev_add_defaultroute(tun->nl, tun->ifindex, AF_INET); |
| if (rc < 0) |
| LOGTUN(tun, LOGL_ERROR, "Cannot add IPv4 default route\n"); |
| else |
| LOGTUN(tun, LOGL_INFO, "Added IPv4 default route\n"); |
| |
| rc = netdev_add_defaultroute(tun->nl, tun->ifindex, AF_INET6); |
| if (rc < 0) |
| LOGTUN(tun, LOGL_ERROR, "Cannot add IPv6 default route\n"); |
| else |
| LOGTUN(tun, LOGL_INFO, "Added IPv6 default route\n"); |
| } |
| |
| if (pthread_create(&tun->thread, NULL, tun_device_thread, tun)) { |
| LOGTUN(tun, LOGL_ERROR, "Cannot create TUN thread: %s\n", strerror(errno)); |
| goto err_free_nl; |
| } |
| |
| LOGTUN(tun, LOGL_INFO, "Created (in netns '%s')\n", tun->netns_name); |
| llist_add_tail(&tun->list, &d->tun_devices); |
| |
| return tun; |
| |
| err_free_nl: |
| nl_socket_free(tun->nl); |
| err_close: |
| close(tun->fd); |
| err_restore_ns: |
| if (tun->netns_name) |
| OSMO_ASSERT(restore_ns(&oldmask) == 0); |
| err_close_ns: |
| if (tun->netns_name) |
| close(tun->netns_fd); |
| err_free: |
| talloc_free(tun); |
| return NULL; |
| } |
| |
| struct tun_device * |
| _tun_device_find(struct gtp_daemon *d, const char *devname) |
| { |
| struct tun_device *tun; |
| |
| llist_for_each_entry(tun, &d->tun_devices, list) { |
| if (!strcmp(tun->devname, devname)) |
| return tun; |
| } |
| return NULL; |
| } |
| |
| /* find the first tun device within given named netns */ |
| struct tun_device * |
| tun_device_find_netns(struct gtp_daemon *d, const char *netns_name) |
| { |
| struct tun_device *tun; |
| |
| pthread_rwlock_rdlock(&d->rwlock); |
| llist_for_each_entry(tun, &d->tun_devices, list) { |
| if (!strcmp(tun->netns_name, netns_name)) { |
| pthread_rwlock_unlock(&d->rwlock); |
| return tun; |
| } |
| } |
| pthread_rwlock_unlock(&d->rwlock); |
| return NULL; |
| } |
| |
| struct tun_device * |
| tun_device_find_or_create(struct gtp_daemon *d, const char *devname, const char *netns_name) |
| { |
| struct tun_device *tun; |
| |
| /* talloc is not thread safe, all alloc/free must come from main thread */ |
| ASSERT_MAIN_THREAD(d); |
| |
| pthread_rwlock_wrlock(&d->rwlock); |
| tun = _tun_device_find(d, devname); |
| if (tun) |
| tun->use_count++; |
| else |
| tun = _tun_device_create(d, devname, netns_name); |
| pthread_rwlock_unlock(&d->rwlock); |
| |
| return tun; |
| } |
| |
| /* UNLOCKED hard/forced destroy; caller must make sure references are cleaned up */ |
| static void _tun_device_destroy(struct tun_device *tun) |
| { |
| /* talloc is not thread safe, all alloc/free must come from main thread */ |
| ASSERT_MAIN_THREAD(tun->d); |
| |
| pthread_cancel(tun->thread); |
| llist_del(&tun->list); |
| if (tun->netns_name) |
| close(tun->netns_fd); |
| close(tun->fd); |
| nl_socket_free(tun->nl); |
| LOGTUN(tun, LOGL_INFO, "Destroying\n"); |
| talloc_free(tun); |
| } |
| |
| /* UNLOCKED remove all objects referencing this tun and then destroy */ |
| void _tun_device_deref_destroy(struct tun_device *tun) |
| { |
| struct gtp_daemon *d = tun->d; |
| char *devname = talloc_strdup(d, tun->devname); |
| struct gtp_tunnel *t, *t2; |
| struct tun_device *tun2; |
| |
| /* talloc is not thread safe, all alloc/free must come from main thread */ |
| ASSERT_MAIN_THREAD(tun->d); |
| |
| llist_for_each_entry_safe(t, t2, &g_daemon->gtp_tunnels, list) { |
| if (t->tun_dev == tun) |
| _gtp_tunnel_destroy(t); |
| } |
| /* _tun_device_destroy may already have been called via |
| * _gtp_tunnel_destroy -> _tun_device_release, so we have to |
| * check if the tun can still be found in the list */ |
| tun2 = _tun_device_find(d, devname); |
| if (tun2 && tun2 == tun) |
| _tun_device_destroy(tun2); |
| |
| talloc_free(devname); |
| } |
| |
| /* UNLOCKED release a reference; destroy if refcount drops to 0 */ |
| bool _tun_device_release(struct tun_device *tun) |
| { |
| bool released = false; |
| |
| /* talloc is not thread safe, all alloc/free must come from main thread */ |
| ASSERT_MAIN_THREAD(tun->d); |
| |
| tun->use_count--; |
| if (tun->use_count == 0) { |
| _tun_device_destroy(tun); |
| released = true; |
| } else |
| LOGTUN(tun, LOGL_DEBUG, "Release; new use_count=%lu\n", tun->use_count); |
| |
| return released; |
| } |
| |
| /* release a reference; destroy if refcount drops to 0 */ |
| bool tun_device_release(struct tun_device *tun) |
| { |
| struct gtp_daemon *d = tun->d; |
| bool released; |
| |
| /* talloc is not thread safe, all alloc/free must come from main thread */ |
| ASSERT_MAIN_THREAD(tun->d); |
| |
| pthread_rwlock_wrlock(&d->rwlock); |
| released = _tun_device_release(tun); |
| pthread_rwlock_unlock(&d->rwlock); |
| |
| return released; |
| } |