diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/net/gtp.c | 1945 |
1 files changed, 1945 insertions, 0 deletions
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c new file mode 100644 index 000000000..bace98959 --- /dev/null +++ b/drivers/net/gtp.c @@ -0,0 +1,1945 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* GTP according to GSM TS 09.60 / 3GPP TS 29.060 + * + * (C) 2012-2014 by sysmocom - s.f.m.c. GmbH + * (C) 2016 by Pablo Neira Ayuso <pablo@netfilter.org> + * + * Author: Harald Welte <hwelte@sysmocom.de> + * Pablo Neira Ayuso <pablo@netfilter.org> + * Andreas Schultz <aschultz@travelping.com> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/udp.h> +#include <linux/rculist.h> +#include <linux/jhash.h> +#include <linux/if_tunnel.h> +#include <linux/net.h> +#include <linux/file.h> +#include <linux/gtp.h> + +#include <net/net_namespace.h> +#include <net/protocol.h> +#include <net/ip.h> +#include <net/udp.h> +#include <net/udp_tunnel.h> +#include <net/icmp.h> +#include <net/xfrm.h> +#include <net/genetlink.h> +#include <net/netns/generic.h> +#include <net/gtp.h> + +/* An active session for the subscriber. */ +struct pdp_ctx { + struct hlist_node hlist_tid; + struct hlist_node hlist_addr; + + union { + struct { + u64 tid; + u16 flow; + } v0; + struct { + u32 i_tei; + u32 o_tei; + } v1; + } u; + u8 gtp_version; + u16 af; + + struct in_addr ms_addr_ip4; + struct in_addr peer_addr_ip4; + + struct sock *sk; + struct net_device *dev; + + atomic_t tx_seq; + struct rcu_head rcu_head; +}; + +/* One instance of the GTP device. */ +struct gtp_dev { + struct list_head list; + + struct sock *sk0; + struct sock *sk1u; + u8 sk_created; + + struct net_device *dev; + struct net *net; + + unsigned int role; + unsigned int hash_size; + struct hlist_head *tid_hash; + struct hlist_head *addr_hash; + + u8 restart_count; +}; + +struct echo_info { + struct in_addr ms_addr_ip4; + struct in_addr peer_addr_ip4; + u8 gtp_version; +}; + +static unsigned int gtp_net_id __read_mostly; + +struct gtp_net { + struct list_head gtp_dev_list; +}; + +static u32 gtp_h_initval; + +static struct genl_family gtp_genl_family; + +enum gtp_multicast_groups { + GTP_GENL_MCGRP, +}; + +static const struct genl_multicast_group gtp_genl_mcgrps[] = { + [GTP_GENL_MCGRP] = { .name = GTP_GENL_MCGRP_NAME }, +}; + +static void pdp_context_delete(struct pdp_ctx *pctx); + +static inline u32 gtp0_hashfn(u64 tid) +{ + u32 *tid32 = (u32 *) &tid; + return jhash_2words(tid32[0], tid32[1], gtp_h_initval); +} + +static inline u32 gtp1u_hashfn(u32 tid) +{ + return jhash_1word(tid, gtp_h_initval); +} + +static inline u32 ipv4_hashfn(__be32 ip) +{ + return jhash_1word((__force u32)ip, gtp_h_initval); +} + +/* Resolve a PDP context structure based on the 64bit TID. */ +static struct pdp_ctx *gtp0_pdp_find(struct gtp_dev *gtp, u64 tid) +{ + struct hlist_head *head; + struct pdp_ctx *pdp; + + head = >p->tid_hash[gtp0_hashfn(tid) % gtp->hash_size]; + + hlist_for_each_entry_rcu(pdp, head, hlist_tid) { + if (pdp->gtp_version == GTP_V0 && + pdp->u.v0.tid == tid) + return pdp; + } + return NULL; +} + +/* Resolve a PDP context structure based on the 32bit TEI. */ +static struct pdp_ctx *gtp1_pdp_find(struct gtp_dev *gtp, u32 tid) +{ + struct hlist_head *head; + struct pdp_ctx *pdp; + + head = >p->tid_hash[gtp1u_hashfn(tid) % gtp->hash_size]; + + hlist_for_each_entry_rcu(pdp, head, hlist_tid) { + if (pdp->gtp_version == GTP_V1 && + pdp->u.v1.i_tei == tid) + return pdp; + } + return NULL; +} + +/* Resolve a PDP context based on IPv4 address of MS. */ +static struct pdp_ctx *ipv4_pdp_find(struct gtp_dev *gtp, __be32 ms_addr) +{ + struct hlist_head *head; + struct pdp_ctx *pdp; + + head = >p->addr_hash[ipv4_hashfn(ms_addr) % gtp->hash_size]; + + hlist_for_each_entry_rcu(pdp, head, hlist_addr) { + if (pdp->af == AF_INET && + pdp->ms_addr_ip4.s_addr == ms_addr) + return pdp; + } + + return NULL; +} + +static bool gtp_check_ms_ipv4(struct sk_buff *skb, struct pdp_ctx *pctx, + unsigned int hdrlen, unsigned int role) +{ + struct iphdr *iph; + + if (!pskb_may_pull(skb, hdrlen + sizeof(struct iphdr))) + return false; + + iph = (struct iphdr *)(skb->data + hdrlen); + + if (role == GTP_ROLE_SGSN) + return iph->daddr == pctx->ms_addr_ip4.s_addr; + else + return iph->saddr == pctx->ms_addr_ip4.s_addr; +} + +/* Check if the inner IP address in this packet is assigned to any + * existing mobile subscriber. + */ +static bool gtp_check_ms(struct sk_buff *skb, struct pdp_ctx *pctx, + unsigned int hdrlen, unsigned int role) +{ + switch (ntohs(skb->protocol)) { + case ETH_P_IP: + return gtp_check_ms_ipv4(skb, pctx, hdrlen, role); + } + return false; +} + +static int gtp_rx(struct pdp_ctx *pctx, struct sk_buff *skb, + unsigned int hdrlen, unsigned int role) +{ + if (!gtp_check_ms(skb, pctx, hdrlen, role)) { + netdev_dbg(pctx->dev, "No PDP ctx for this MS\n"); + return 1; + } + + /* Get rid of the GTP + UDP headers. */ + if (iptunnel_pull_header(skb, hdrlen, skb->protocol, + !net_eq(sock_net(pctx->sk), dev_net(pctx->dev)))) { + pctx->dev->stats.rx_length_errors++; + goto err; + } + + netdev_dbg(pctx->dev, "forwarding packet from GGSN to uplink\n"); + + /* Now that the UDP and the GTP header have been removed, set up the + * new network header. This is required by the upper layer to + * calculate the transport header. + */ + skb_reset_network_header(skb); + skb_reset_mac_header(skb); + + skb->dev = pctx->dev; + + dev_sw_netstats_rx_add(pctx->dev, skb->len); + + __netif_rx(skb); + return 0; + +err: + pctx->dev->stats.rx_dropped++; + return -1; +} + +static struct rtable *ip4_route_output_gtp(struct flowi4 *fl4, + const struct sock *sk, + __be32 daddr, __be32 saddr) +{ + memset(fl4, 0, sizeof(*fl4)); + fl4->flowi4_oif = sk->sk_bound_dev_if; + fl4->daddr = daddr; + fl4->saddr = saddr; + fl4->flowi4_tos = RT_CONN_FLAGS(sk); + fl4->flowi4_proto = sk->sk_protocol; + + return ip_route_output_key(sock_net(sk), fl4); +} + +/* GSM TS 09.60. 7.3 + * In all Path Management messages: + * - TID: is not used and shall be set to 0. + * - Flow Label is not used and shall be set to 0 + * In signalling messages: + * - number: this field is not yet used in signalling messages. + * It shall be set to 255 by the sender and shall be ignored + * by the receiver + * Returns true if the echo req was correct, false otherwise. + */ +static bool gtp0_validate_echo_hdr(struct gtp0_header *gtp0) +{ + return !(gtp0->tid || (gtp0->flags ^ 0x1e) || + gtp0->number != 0xff || gtp0->flow); +} + +/* msg_type has to be GTP_ECHO_REQ or GTP_ECHO_RSP */ +static void gtp0_build_echo_msg(struct gtp0_header *hdr, __u8 msg_type) +{ + int len_pkt, len_hdr; + + hdr->flags = 0x1e; /* v0, GTP-non-prime. */ + hdr->type = msg_type; + /* GSM TS 09.60. 7.3 In all Path Management Flow Label and TID + * are not used and shall be set to 0. + */ + hdr->flow = 0; + hdr->tid = 0; + hdr->number = 0xff; + hdr->spare[0] = 0xff; + hdr->spare[1] = 0xff; + hdr->spare[2] = 0xff; + + len_pkt = sizeof(struct gtp0_packet); + len_hdr = sizeof(struct gtp0_header); + + if (msg_type == GTP_ECHO_RSP) + hdr->length = htons(len_pkt - len_hdr); + else + hdr->length = 0; +} + +static int gtp0_send_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb) +{ + struct gtp0_packet *gtp_pkt; + struct gtp0_header *gtp0; + struct rtable *rt; + struct flowi4 fl4; + struct iphdr *iph; + __be16 seq; + + gtp0 = (struct gtp0_header *)(skb->data + sizeof(struct udphdr)); + + if (!gtp0_validate_echo_hdr(gtp0)) + return -1; + + seq = gtp0->seq; + + /* pull GTP and UDP headers */ + skb_pull_data(skb, sizeof(struct gtp0_header) + sizeof(struct udphdr)); + + gtp_pkt = skb_push(skb, sizeof(struct gtp0_packet)); + memset(gtp_pkt, 0, sizeof(struct gtp0_packet)); + + gtp0_build_echo_msg(>p_pkt->gtp0_h, GTP_ECHO_RSP); + + /* GSM TS 09.60. 7.3 The Sequence Number in a signalling response + * message shall be copied from the signalling request message + * that the GSN is replying to. + */ + gtp_pkt->gtp0_h.seq = seq; + + gtp_pkt->ie.tag = GTPIE_RECOVERY; + gtp_pkt->ie.val = gtp->restart_count; + + iph = ip_hdr(skb); + + /* find route to the sender, + * src address becomes dst address and vice versa. + */ + rt = ip4_route_output_gtp(&fl4, gtp->sk0, iph->saddr, iph->daddr); + if (IS_ERR(rt)) { + netdev_dbg(gtp->dev, "no route for echo response from %pI4\n", + &iph->saddr); + return -1; + } + + udp_tunnel_xmit_skb(rt, gtp->sk0, skb, + fl4.saddr, fl4.daddr, + iph->tos, + ip4_dst_hoplimit(&rt->dst), + 0, + htons(GTP0_PORT), htons(GTP0_PORT), + !net_eq(sock_net(gtp->sk1u), + dev_net(gtp->dev)), + false); + return 0; +} + +static int gtp_genl_fill_echo(struct sk_buff *skb, u32 snd_portid, u32 snd_seq, + int flags, u32 type, struct echo_info echo) +{ + void *genlh; + + genlh = genlmsg_put(skb, snd_portid, snd_seq, >p_genl_family, flags, + type); + if (!genlh) + goto failure; + + if (nla_put_u32(skb, GTPA_VERSION, echo.gtp_version) || + nla_put_be32(skb, GTPA_PEER_ADDRESS, echo.peer_addr_ip4.s_addr) || + nla_put_be32(skb, GTPA_MS_ADDRESS, echo.ms_addr_ip4.s_addr)) + goto failure; + + genlmsg_end(skb, genlh); + return 0; + +failure: + genlmsg_cancel(skb, genlh); + return -EMSGSIZE; +} + +static int gtp0_handle_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb) +{ + struct gtp0_header *gtp0; + struct echo_info echo; + struct sk_buff *msg; + struct iphdr *iph; + int ret; + + gtp0 = (struct gtp0_header *)(skb->data + sizeof(struct udphdr)); + + if (!gtp0_validate_echo_hdr(gtp0)) + return -1; + + iph = ip_hdr(skb); + echo.ms_addr_ip4.s_addr = iph->daddr; + echo.peer_addr_ip4.s_addr = iph->saddr; + echo.gtp_version = GTP_V0; + + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); + if (!msg) + return -ENOMEM; + + ret = gtp_genl_fill_echo(msg, 0, 0, 0, GTP_CMD_ECHOREQ, echo); + if (ret < 0) { + nlmsg_free(msg); + return ret; + } + + return genlmsg_multicast_netns(>p_genl_family, dev_net(gtp->dev), + msg, 0, GTP_GENL_MCGRP, GFP_ATOMIC); +} + +/* 1 means pass up to the stack, -1 means drop and 0 means decapsulated. */ +static int gtp0_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb) +{ + unsigned int hdrlen = sizeof(struct udphdr) + + sizeof(struct gtp0_header); + struct gtp0_header *gtp0; + struct pdp_ctx *pctx; + + if (!pskb_may_pull(skb, hdrlen)) + return -1; + + gtp0 = (struct gtp0_header *)(skb->data + sizeof(struct udphdr)); + + if ((gtp0->flags >> 5) != GTP_V0) + return 1; + + /* If the sockets were created in kernel, it means that + * there is no daemon running in userspace which would + * handle echo request. + */ + if (gtp0->type == GTP_ECHO_REQ && gtp->sk_created) + return gtp0_send_echo_resp(gtp, skb); + + if (gtp0->type == GTP_ECHO_RSP && gtp->sk_created) + return gtp0_handle_echo_resp(gtp, skb); + + if (gtp0->type != GTP_TPDU) + return 1; + + pctx = gtp0_pdp_find(gtp, be64_to_cpu(gtp0->tid)); + if (!pctx) { + netdev_dbg(gtp->dev, "No PDP ctx to decap skb=%p\n", skb); + return 1; + } + + return gtp_rx(pctx, skb, hdrlen, gtp->role); +} + +/* msg_type has to be GTP_ECHO_REQ or GTP_ECHO_RSP */ +static void gtp1u_build_echo_msg(struct gtp1_header_long *hdr, __u8 msg_type) +{ + int len_pkt, len_hdr; + + /* S flag must be set to 1 */ + hdr->flags = 0x32; /* v1, GTP-non-prime. */ + hdr->type = msg_type; + /* 3GPP TS 29.281 5.1 - TEID has to be set to 0 */ + hdr->tid = 0; + + /* seq, npdu and next should be counted to the length of the GTP packet + * that's why szie of gtp1_header should be subtracted, + * not size of gtp1_header_long. + */ + + len_hdr = sizeof(struct gtp1_header); + + if (msg_type == GTP_ECHO_RSP) { + len_pkt = sizeof(struct gtp1u_packet); + hdr->length = htons(len_pkt - len_hdr); + } else { + /* GTP_ECHO_REQ does not carry GTP Information Element, + * the why gtp1_header_long is used here. + */ + len_pkt = sizeof(struct gtp1_header_long); + hdr->length = htons(len_pkt - len_hdr); + } +} + +static int gtp1u_send_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb) +{ + struct gtp1_header_long *gtp1u; + struct gtp1u_packet *gtp_pkt; + struct rtable *rt; + struct flowi4 fl4; + struct iphdr *iph; + + gtp1u = (struct gtp1_header_long *)(skb->data + sizeof(struct udphdr)); + + /* 3GPP TS 29.281 5.1 - For the Echo Request, Echo Response, + * Error Indication and Supported Extension Headers Notification + * messages, the S flag shall be set to 1 and TEID shall be set to 0. + */ + if (!(gtp1u->flags & GTP1_F_SEQ) || gtp1u->tid) + return -1; + + /* pull GTP and UDP headers */ + skb_pull_data(skb, + sizeof(struct gtp1_header_long) + sizeof(struct udphdr)); + + gtp_pkt = skb_push(skb, sizeof(struct gtp1u_packet)); + memset(gtp_pkt, 0, sizeof(struct gtp1u_packet)); + + gtp1u_build_echo_msg(>p_pkt->gtp1u_h, GTP_ECHO_RSP); + + /* 3GPP TS 29.281 7.7.2 - The Restart Counter value in the + * Recovery information element shall not be used, i.e. it shall + * be set to zero by the sender and shall be ignored by the receiver. + * The Recovery information element is mandatory due to backwards + * compatibility reasons. + */ + gtp_pkt->ie.tag = GTPIE_RECOVERY; + gtp_pkt->ie.val = 0; + + iph = ip_hdr(skb); + + /* find route to the sender, + * src address becomes dst address and vice versa. + */ + rt = ip4_route_output_gtp(&fl4, gtp->sk1u, iph->saddr, iph->daddr); + if (IS_ERR(rt)) { + netdev_dbg(gtp->dev, "no route for echo response from %pI4\n", + &iph->saddr); + return -1; + } + + udp_tunnel_xmit_skb(rt, gtp->sk1u, skb, + fl4.saddr, fl4.daddr, + iph->tos, + ip4_dst_hoplimit(&rt->dst), + 0, + htons(GTP1U_PORT), htons(GTP1U_PORT), + !net_eq(sock_net(gtp->sk1u), + dev_net(gtp->dev)), + false); + return 0; +} + +static int gtp1u_handle_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb) +{ + struct gtp1_header_long *gtp1u; + struct echo_info echo; + struct sk_buff *msg; + struct iphdr *iph; + int ret; + + gtp1u = (struct gtp1_header_long *)(skb->data + sizeof(struct udphdr)); + + /* 3GPP TS 29.281 5.1 - For the Echo Request, Echo Response, + * Error Indication and Supported Extension Headers Notification + * messages, the S flag shall be set to 1 and TEID shall be set to 0. + */ + if (!(gtp1u->flags & GTP1_F_SEQ) || gtp1u->tid) + return -1; + + iph = ip_hdr(skb); + echo.ms_addr_ip4.s_addr = iph->daddr; + echo.peer_addr_ip4.s_addr = iph->saddr; + echo.gtp_version = GTP_V1; + + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); + if (!msg) + return -ENOMEM; + + ret = gtp_genl_fill_echo(msg, 0, 0, 0, GTP_CMD_ECHOREQ, echo); + if (ret < 0) { + nlmsg_free(msg); + return ret; + } + + return genlmsg_multicast_netns(>p_genl_family, dev_net(gtp->dev), + msg, 0, GTP_GENL_MCGRP, GFP_ATOMIC); +} + +static int gtp1u_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb) +{ + unsigned int hdrlen = sizeof(struct udphdr) + + sizeof(struct gtp1_header); + struct gtp1_header *gtp1; + struct pdp_ctx *pctx; + + if (!pskb_may_pull(skb, hdrlen)) + return -1; + + gtp1 = (struct gtp1_header *)(skb->data + sizeof(struct udphdr)); + + if ((gtp1->flags >> 5) != GTP_V1) + return 1; + + /* If the sockets were created in kernel, it means that + * there is no daemon running in userspace which would + * handle echo request. + */ + if (gtp1->type == GTP_ECHO_REQ && gtp->sk_created) + return gtp1u_send_echo_resp(gtp, skb); + + if (gtp1->type == GTP_ECHO_RSP && gtp->sk_created) + return gtp1u_handle_echo_resp(gtp, skb); + + if (gtp1->type != GTP_TPDU) + return 1; + + /* From 29.060: "This field shall be present if and only if any one or + * more of the S, PN and E flags are set.". + * + * If any of the bit is set, then the remaining ones also have to be + * set. + */ + if (gtp1->flags & GTP1_F_MASK) + hdrlen += 4; + + /* Make sure the header is larger enough, including extensions. */ + if (!pskb_may_pull(skb, hdrlen)) + return -1; + + gtp1 = (struct gtp1_header *)(skb->data + sizeof(struct udphdr)); + + pctx = gtp1_pdp_find(gtp, ntohl(gtp1->tid)); + if (!pctx) { + netdev_dbg(gtp->dev, "No PDP ctx to decap skb=%p\n", skb); + return 1; + } + + return gtp_rx(pctx, skb, hdrlen, gtp->role); +} + +static void __gtp_encap_destroy(struct sock *sk) +{ + struct gtp_dev *gtp; + + lock_sock(sk); + gtp = sk->sk_user_data; + if (gtp) { + if (gtp->sk0 == sk) + gtp->sk0 = NULL; + else + gtp->sk1u = NULL; + WRITE_ONCE(udp_sk(sk)->encap_type, 0); + rcu_assign_sk_user_data(sk, NULL); + release_sock(sk); + sock_put(sk); + return; + } + release_sock(sk); +} + +static void gtp_encap_destroy(struct sock *sk) +{ + rtnl_lock(); + __gtp_encap_destroy(sk); + rtnl_unlock(); +} + +static void gtp_encap_disable_sock(struct sock *sk) +{ + if (!sk) + return; + + __gtp_encap_destroy(sk); +} + +static void gtp_encap_disable(struct gtp_dev *gtp) +{ + if (gtp->sk_created) { + udp_tunnel_sock_release(gtp->sk0->sk_socket); + udp_tunnel_sock_release(gtp->sk1u->sk_socket); + gtp->sk_created = false; + gtp->sk0 = NULL; + gtp->sk1u = NULL; + } else { + gtp_encap_disable_sock(gtp->sk0); + gtp_encap_disable_sock(gtp->sk1u); + } +} + +/* UDP encapsulation receive handler. See net/ipv4/udp.c. + * Return codes: 0: success, <0: error, >0: pass up to userspace UDP socket. + */ +static int gtp_encap_recv(struct sock *sk, struct sk_buff *skb) +{ + struct gtp_dev *gtp; + int ret = 0; + + gtp = rcu_dereference_sk_user_data(sk); + if (!gtp) + return 1; + + netdev_dbg(gtp->dev, "encap_recv sk=%p\n", sk); + + switch (READ_ONCE(udp_sk(sk)->encap_type)) { + case UDP_ENCAP_GTP0: + netdev_dbg(gtp->dev, "received GTP0 packet\n"); + ret = gtp0_udp_encap_recv(gtp, skb); + break; + case UDP_ENCAP_GTP1U: + netdev_dbg(gtp->dev, "received GTP1U packet\n"); + ret = gtp1u_udp_encap_recv(gtp, skb); + break; + default: + ret = -1; /* Shouldn't happen. */ + } + + switch (ret) { + case 1: + netdev_dbg(gtp->dev, "pass up to the process\n"); + break; + case 0: + break; + case -1: + netdev_dbg(gtp->dev, "GTP packet has been dropped\n"); + kfree_skb(skb); + ret = 0; + break; + } + + return ret; +} + +static int gtp_dev_init(struct net_device *dev) +{ + struct gtp_dev *gtp = netdev_priv(dev); + + gtp->dev = dev; + + dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats); + if (!dev->tstats) + return -ENOMEM; + + return 0; +} + +static void gtp_dev_uninit(struct net_device *dev) +{ + struct gtp_dev *gtp = netdev_priv(dev); + + gtp_encap_disable(gtp); + free_percpu(dev->tstats); +} + +static inline void gtp0_push_header(struct sk_buff *skb, struct pdp_ctx *pctx) +{ + int payload_len = skb->len; + struct gtp0_header *gtp0; + + gtp0 = skb_push(skb, sizeof(*gtp0)); + + gtp0->flags = 0x1e; /* v0, GTP-non-prime. */ + gtp0->type = GTP_TPDU; + gtp0->length = htons(payload_len); + gtp0->seq = htons((atomic_inc_return(&pctx->tx_seq) - 1) % 0xffff); + gtp0->flow = htons(pctx->u.v0.flow); + gtp0->number = 0xff; + gtp0->spare[0] = gtp0->spare[1] = gtp0->spare[2] = 0xff; + gtp0->tid = cpu_to_be64(pctx->u.v0.tid); +} + +static inline void gtp1_push_header(struct sk_buff *skb, struct pdp_ctx *pctx) +{ + int payload_len = skb->len; + struct gtp1_header *gtp1; + + gtp1 = skb_push(skb, sizeof(*gtp1)); + + /* Bits 8 7 6 5 4 3 2 1 + * +--+--+--+--+--+--+--+--+ + * |version |PT| 0| E| S|PN| + * +--+--+--+--+--+--+--+--+ + * 0 0 1 1 1 0 0 0 + */ + gtp1->flags = 0x30; /* v1, GTP-non-prime. */ + gtp1->type = GTP_TPDU; + gtp1->length = htons(payload_len); + gtp1->tid = htonl(pctx->u.v1.o_tei); + + /* TODO: Support for extension header, sequence number and N-PDU. + * Update the length field if any of them is available. + */ +} + +struct gtp_pktinfo { + struct sock *sk; + struct iphdr *iph; + struct flowi4 fl4; + struct rtable *rt; + struct pdp_ctx *pctx; + struct net_device *dev; + __be16 gtph_port; +}; + +static void gtp_push_header(struct sk_buff *skb, struct gtp_pktinfo *pktinfo) +{ + switch (pktinfo->pctx->gtp_version) { + case GTP_V0: + pktinfo->gtph_port = htons(GTP0_PORT); + gtp0_push_header(skb, pktinfo->pctx); + break; + case GTP_V1: + pktinfo->gtph_port = htons(GTP1U_PORT); + gtp1_push_header(skb, pktinfo->pctx); + break; + } +} + +static inline void gtp_set_pktinfo_ipv4(struct gtp_pktinfo *pktinfo, + struct sock *sk, struct iphdr *iph, + struct pdp_ctx *pctx, struct rtable *rt, + struct flowi4 *fl4, + struct net_device *dev) +{ + pktinfo->sk = sk; + pktinfo->iph = iph; + pktinfo->pctx = pctx; + pktinfo->rt = rt; + pktinfo->fl4 = *fl4; + pktinfo->dev = dev; +} + +static int gtp_build_skb_ip4(struct sk_buff *skb, struct net_device *dev, + struct gtp_pktinfo *pktinfo) +{ + struct gtp_dev *gtp = netdev_priv(dev); + struct pdp_ctx *pctx; + struct rtable *rt; + struct flowi4 fl4; + struct iphdr *iph; + __be16 df; + int mtu; + + /* Read the IP destination address and resolve the PDP context. + * Prepend PDP header with TEI/TID from PDP ctx. + */ + iph = ip_hdr(skb); + if (gtp->role == GTP_ROLE_SGSN) + pctx = ipv4_pdp_find(gtp, iph->saddr); + else + pctx = ipv4_pdp_find(gtp, iph->daddr); + + if (!pctx) { + netdev_dbg(dev, "no PDP ctx found for %pI4, skip\n", + &iph->daddr); + return -ENOENT; + } + netdev_dbg(dev, "found PDP context %p\n", pctx); + + rt = ip4_route_output_gtp(&fl4, pctx->sk, pctx->peer_addr_ip4.s_addr, + inet_sk(pctx->sk)->inet_saddr); + if (IS_ERR(rt)) { + netdev_dbg(dev, "no route to SSGN %pI4\n", + &pctx->peer_addr_ip4.s_addr); + dev->stats.tx_carrier_errors++; + goto err; + } + + if (rt->dst.dev == dev) { + netdev_dbg(dev, "circular route to SSGN %pI4\n", + &pctx->peer_addr_ip4.s_addr); + dev->stats.collisions++; + goto err_rt; + } + + /* This is similar to tnl_update_pmtu(). */ + df = iph->frag_off; + if (df) { + mtu = dst_mtu(&rt->dst) - dev->hard_header_len - + sizeof(struct iphdr) - sizeof(struct udphdr); + switch (pctx->gtp_version) { + case GTP_V0: + mtu -= sizeof(struct gtp0_header); + break; + case GTP_V1: + mtu -= sizeof(struct gtp1_header); + break; + } + } else { + mtu = dst_mtu(&rt->dst); + } + + skb_dst_update_pmtu_no_confirm(skb, mtu); + + if (iph->frag_off & htons(IP_DF) && + ((!skb_is_gso(skb) && skb->len > mtu) || + (skb_is_gso(skb) && !skb_gso_validate_network_len(skb, mtu)))) { + netdev_dbg(dev, "packet too big, fragmentation needed\n"); + icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, + htonl(mtu)); + goto err_rt; + } + + gtp_set_pktinfo_ipv4(pktinfo, pctx->sk, iph, pctx, rt, &fl4, dev); + gtp_push_header(skb, pktinfo); + + return 0; +err_rt: + ip_rt_put(rt); +err: + return -EBADMSG; +} + +static netdev_tx_t gtp_dev_xmit(struct sk_buff *skb, struct net_device *dev) +{ + unsigned int proto = ntohs(skb->protocol); + struct gtp_pktinfo pktinfo; + int err; + + /* Ensure there is sufficient headroom. */ + if (skb_cow_head(skb, dev->needed_headroom)) + goto tx_err; + + skb_reset_inner_headers(skb); + + /* PDP context lookups in gtp_build_skb_*() need rcu read-side lock. */ + rcu_read_lock(); + switch (proto) { + case ETH_P_IP: + err = gtp_build_skb_ip4(skb, dev, &pktinfo); + break; + default: + err = -EOPNOTSUPP; + break; + } + rcu_read_unlock(); + + if (err < 0) + goto tx_err; + + switch (proto) { + case ETH_P_IP: + netdev_dbg(pktinfo.dev, "gtp -> IP src: %pI4 dst: %pI4\n", + &pktinfo.iph->saddr, &pktinfo.iph->daddr); + udp_tunnel_xmit_skb(pktinfo.rt, pktinfo.sk, skb, + pktinfo.fl4.saddr, pktinfo.fl4.daddr, + pktinfo.iph->tos, + ip4_dst_hoplimit(&pktinfo.rt->dst), + 0, + pktinfo.gtph_port, pktinfo.gtph_port, + !net_eq(sock_net(pktinfo.pctx->sk), + dev_net(dev)), + false); + break; + } + + return NETDEV_TX_OK; +tx_err: + dev->stats.tx_errors++; + dev_kfree_skb(skb); + return NETDEV_TX_OK; +} + +static const struct net_device_ops gtp_netdev_ops = { + .ndo_init = gtp_dev_init, + .ndo_uninit = gtp_dev_uninit, + .ndo_start_xmit = gtp_dev_xmit, + .ndo_get_stats64 = dev_get_tstats64, +}; + +static const struct device_type gtp_type = { + .name = "gtp", +}; + +static void gtp_link_setup(struct net_device *dev) +{ + unsigned int max_gtp_header_len = sizeof(struct iphdr) + + sizeof(struct udphdr) + + sizeof(struct gtp0_header); + + dev->netdev_ops = >p_netdev_ops; + dev->needs_free_netdev = true; + SET_NETDEV_DEVTYPE(dev, >p_type); + + dev->hard_header_len = 0; + dev->addr_len = 0; + dev->mtu = ETH_DATA_LEN - max_gtp_header_len; + + /* Zero header length. */ + dev->type = ARPHRD_NONE; + dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; + + dev->priv_flags |= IFF_NO_QUEUE; + dev->features |= NETIF_F_LLTX; + netif_keep_dst(dev); + + dev->needed_headroom = LL_MAX_HEADER + max_gtp_header_len; +} + +static int gtp_hashtable_new(struct gtp_dev *gtp, int hsize); +static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[]); + +static void gtp_destructor(struct net_device *dev) +{ + struct gtp_dev *gtp = netdev_priv(dev); + + kfree(gtp->addr_hash); + kfree(gtp->tid_hash); +} + +static struct sock *gtp_create_sock(int type, struct gtp_dev *gtp) +{ + struct udp_tunnel_sock_cfg tuncfg = {}; + struct udp_port_cfg udp_conf = { + .local_ip.s_addr = htonl(INADDR_ANY), + .family = AF_INET, + }; + struct net *net = gtp->net; + struct socket *sock; + int err; + + if (type == UDP_ENCAP_GTP0) + udp_conf.local_udp_port = htons(GTP0_PORT); + else if (type == UDP_ENCAP_GTP1U) + udp_conf.local_udp_port = htons(GTP1U_PORT); + else + return ERR_PTR(-EINVAL); + + err = udp_sock_create(net, &udp_conf, &sock); + if (err) + return ERR_PTR(err); + + tuncfg.sk_user_data = gtp; + tuncfg.encap_type = type; + tuncfg.encap_rcv = gtp_encap_recv; + tuncfg.encap_destroy = NULL; + + setup_udp_tunnel_sock(net, sock, &tuncfg); + + return sock->sk; +} + +static int gtp_create_sockets(struct gtp_dev *gtp, struct nlattr *data[]) +{ + struct sock *sk1u = NULL; + struct sock *sk0 = NULL; + + sk0 = gtp_create_sock(UDP_ENCAP_GTP0, gtp); + if (IS_ERR(sk0)) + return PTR_ERR(sk0); + + sk1u = gtp_create_sock(UDP_ENCAP_GTP1U, gtp); + if (IS_ERR(sk1u)) { + udp_tunnel_sock_release(sk0->sk_socket); + return PTR_ERR(sk1u); + } + + gtp->sk_created = true; + gtp->sk0 = sk0; + gtp->sk1u = sk1u; + + return 0; +} + +static int gtp_newlink(struct net *src_net, struct net_device *dev, + struct nlattr *tb[], struct nlattr *data[], + struct netlink_ext_ack *extack) +{ + unsigned int role = GTP_ROLE_GGSN; + struct gtp_dev *gtp; + struct gtp_net *gn; + int hashsize, err; + + gtp = netdev_priv(dev); + + if (!data[IFLA_GTP_PDP_HASHSIZE]) { + hashsize = 1024; + } else { + hashsize = nla_get_u32(data[IFLA_GTP_PDP_HASHSIZE]); + if (!hashsize) + hashsize = 1024; + } + + if (data[IFLA_GTP_ROLE]) { + role = nla_get_u32(data[IFLA_GTP_ROLE]); + if (role > GTP_ROLE_SGSN) + return -EINVAL; + } + gtp->role = role; + + if (!data[IFLA_GTP_RESTART_COUNT]) + gtp->restart_count = 0; + else + gtp->restart_count = nla_get_u8(data[IFLA_GTP_RESTART_COUNT]); + + gtp->net = src_net; + + err = gtp_hashtable_new(gtp, hashsize); + if (err < 0) + return err; + + if (data[IFLA_GTP_CREATE_SOCKETS]) + err = gtp_create_sockets(gtp, data); + else + err = gtp_encap_enable(gtp, data); + if (err < 0) + goto out_hashtable; + + err = register_netdevice(dev); + if (err < 0) { + netdev_dbg(dev, "failed to register new netdev %d\n", err); + goto out_encap; + } + + gn = net_generic(dev_net(dev), gtp_net_id); + list_add_rcu(>p->list, &gn->gtp_dev_list); + dev->priv_destructor = gtp_destructor; + + netdev_dbg(dev, "registered new GTP interface\n"); + + return 0; + +out_encap: + gtp_encap_disable(gtp); +out_hashtable: + kfree(gtp->addr_hash); + kfree(gtp->tid_hash); + return err; +} + +static void gtp_dellink(struct net_device *dev, struct list_head *head) +{ + struct gtp_dev *gtp = netdev_priv(dev); + struct pdp_ctx *pctx; + int i; + + for (i = 0; i < gtp->hash_size; i++) + hlist_for_each_entry_rcu(pctx, >p->tid_hash[i], hlist_tid) + pdp_context_delete(pctx); + + list_del_rcu(>p->list); + unregister_netdevice_queue(dev, head); +} + +static const struct nla_policy gtp_policy[IFLA_GTP_MAX + 1] = { + [IFLA_GTP_FD0] = { .type = NLA_U32 }, + [IFLA_GTP_FD1] = { .type = NLA_U32 }, + [IFLA_GTP_PDP_HASHSIZE] = { .type = NLA_U32 }, + [IFLA_GTP_ROLE] = { .type = NLA_U32 }, + [IFLA_GTP_CREATE_SOCKETS] = { .type = NLA_U8 }, + [IFLA_GTP_RESTART_COUNT] = { .type = NLA_U8 }, +}; + +static int gtp_validate(struct nlattr *tb[], struct nlattr *data[], + struct netlink_ext_ack *extack) +{ + if (!data) + return -EINVAL; + + return 0; +} + +static size_t gtp_get_size(const struct net_device *dev) +{ + return nla_total_size(sizeof(__u32)) + /* IFLA_GTP_PDP_HASHSIZE */ + nla_total_size(sizeof(__u32)) + /* IFLA_GTP_ROLE */ + nla_total_size(sizeof(__u8)); /* IFLA_GTP_RESTART_COUNT */ +} + +static int gtp_fill_info(struct sk_buff *skb, const struct net_device *dev) +{ + struct gtp_dev *gtp = netdev_priv(dev); + + if (nla_put_u32(skb, IFLA_GTP_PDP_HASHSIZE, gtp->hash_size)) + goto nla_put_failure; + if (nla_put_u32(skb, IFLA_GTP_ROLE, gtp->role)) + goto nla_put_failure; + if (nla_put_u8(skb, IFLA_GTP_RESTART_COUNT, gtp->restart_count)) + goto nla_put_failure; + + return 0; + +nla_put_failure: + return -EMSGSIZE; +} + +static struct rtnl_link_ops gtp_link_ops __read_mostly = { + .kind = "gtp", + .maxtype = IFLA_GTP_MAX, + .policy = gtp_policy, + .priv_size = sizeof(struct gtp_dev), + .setup = gtp_link_setup, + .validate = gtp_validate, + .newlink = gtp_newlink, + .dellink = gtp_dellink, + .get_size = gtp_get_size, + .fill_info = gtp_fill_info, +}; + +static int gtp_hashtable_new(struct gtp_dev *gtp, int hsize) +{ + int i; + + gtp->addr_hash = kmalloc_array(hsize, sizeof(struct hlist_head), + GFP_KERNEL | __GFP_NOWARN); + if (gtp->addr_hash == NULL) + return -ENOMEM; + + gtp->tid_hash = kmalloc_array(hsize, sizeof(struct hlist_head), + GFP_KERNEL | __GFP_NOWARN); + if (gtp->tid_hash == NULL) + goto err1; + + gtp->hash_size = hsize; + + for (i = 0; i < hsize; i++) { + INIT_HLIST_HEAD(>p->addr_hash[i]); + INIT_HLIST_HEAD(>p->tid_hash[i]); + } + return 0; +err1: + kfree(gtp->addr_hash); + return -ENOMEM; +} + +static struct sock *gtp_encap_enable_socket(int fd, int type, + struct gtp_dev *gtp) +{ + struct udp_tunnel_sock_cfg tuncfg = {NULL}; + struct socket *sock; + struct sock *sk; + int err; + + pr_debug("enable gtp on %d, %d\n", fd, type); + + sock = sockfd_lookup(fd, &err); + if (!sock) { + pr_debug("gtp socket fd=%d not found\n", fd); + return NULL; + } + + sk = sock->sk; + if (sk->sk_protocol != IPPROTO_UDP || + sk->sk_type != SOCK_DGRAM || + (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)) { + pr_debug("socket fd=%d not UDP\n", fd); + sk = ERR_PTR(-EINVAL); + goto out_sock; + } + + lock_sock(sk); + if (sk->sk_user_data) { + sk = ERR_PTR(-EBUSY); + goto out_rel_sock; + } + + sock_hold(sk); + + tuncfg.sk_user_data = gtp; + tuncfg.encap_type = type; + tuncfg.encap_rcv = gtp_encap_recv; + tuncfg.encap_destroy = gtp_encap_destroy; + + setup_udp_tunnel_sock(sock_net(sock->sk), sock, &tuncfg); + +out_rel_sock: + release_sock(sock->sk); +out_sock: + sockfd_put(sock); + return sk; +} + +static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[]) +{ + struct sock *sk1u = NULL; + struct sock *sk0 = NULL; + + if (!data[IFLA_GTP_FD0] && !data[IFLA_GTP_FD1]) + return -EINVAL; + + if (data[IFLA_GTP_FD0]) { + u32 fd0 = nla_get_u32(data[IFLA_GTP_FD0]); + + sk0 = gtp_encap_enable_socket(fd0, UDP_ENCAP_GTP0, gtp); + if (IS_ERR(sk0)) + return PTR_ERR(sk0); + } + + if (data[IFLA_GTP_FD1]) { + u32 fd1 = nla_get_u32(data[IFLA_GTP_FD1]); + + sk1u = gtp_encap_enable_socket(fd1, UDP_ENCAP_GTP1U, gtp); + if (IS_ERR(sk1u)) { + gtp_encap_disable_sock(sk0); + return PTR_ERR(sk1u); + } + } + + gtp->sk0 = sk0; + gtp->sk1u = sk1u; + + return 0; +} + +static struct gtp_dev *gtp_find_dev(struct net *src_net, struct nlattr *nla[]) +{ + struct gtp_dev *gtp = NULL; + struct net_device *dev; + struct net *net; + + /* Examine the link attributes and figure out which network namespace + * we are talking about. + */ + if (nla[GTPA_NET_NS_FD]) + net = get_net_ns_by_fd(nla_get_u32(nla[GTPA_NET_NS_FD])); + else + net = get_net(src_net); + + if (IS_ERR(net)) + return NULL; + + /* Check if there's an existing gtpX device to configure */ + dev = dev_get_by_index_rcu(net, nla_get_u32(nla[GTPA_LINK])); + if (dev && dev->netdev_ops == >p_netdev_ops) + gtp = netdev_priv(dev); + + put_net(net); + return gtp; +} + +static void ipv4_pdp_fill(struct pdp_ctx *pctx, struct genl_info *info) +{ + pctx->gtp_version = nla_get_u32(info->attrs[GTPA_VERSION]); + pctx->af = AF_INET; + pctx->peer_addr_ip4.s_addr = + nla_get_be32(info->attrs[GTPA_PEER_ADDRESS]); + pctx->ms_addr_ip4.s_addr = + nla_get_be32(info->attrs[GTPA_MS_ADDRESS]); + + switch (pctx->gtp_version) { + case GTP_V0: + /* According to TS 09.60, sections 7.5.1 and 7.5.2, the flow + * label needs to be the same for uplink and downlink packets, + * so let's annotate this. + */ + pctx->u.v0.tid = nla_get_u64(info->attrs[GTPA_TID]); + pctx->u.v0.flow = nla_get_u16(info->attrs[GTPA_FLOW]); + break; + case GTP_V1: + pctx->u.v1.i_tei = nla_get_u32(info->attrs[GTPA_I_TEI]); + pctx->u.v1.o_tei = nla_get_u32(info->attrs[GTPA_O_TEI]); + break; + default: + break; + } +} + +static struct pdp_ctx *gtp_pdp_add(struct gtp_dev *gtp, struct sock *sk, + struct genl_info *info) +{ + struct pdp_ctx *pctx, *pctx_tid = NULL; + struct net_device *dev = gtp->dev; + u32 hash_ms, hash_tid = 0; + unsigned int version; + bool found = false; + __be32 ms_addr; + + ms_addr = nla_get_be32(info->attrs[GTPA_MS_ADDRESS]); + hash_ms = ipv4_hashfn(ms_addr) % gtp->hash_size; + version = nla_get_u32(info->attrs[GTPA_VERSION]); + + pctx = ipv4_pdp_find(gtp, ms_addr); + if (pctx) + found = true; + if (version == GTP_V0) + pctx_tid = gtp0_pdp_find(gtp, + nla_get_u64(info->attrs[GTPA_TID])); + else if (version == GTP_V1) + pctx_tid = gtp1_pdp_find(gtp, + nla_get_u32(info->attrs[GTPA_I_TEI])); + if (pctx_tid) + found = true; + + if (found) { + if (info->nlhdr->nlmsg_flags & NLM_F_EXCL) + return ERR_PTR(-EEXIST); + if (info->nlhdr->nlmsg_flags & NLM_F_REPLACE) + return ERR_PTR(-EOPNOTSUPP); + + if (pctx && pctx_tid) + return ERR_PTR(-EEXIST); + if (!pctx) + pctx = pctx_tid; + + ipv4_pdp_fill(pctx, info); + + if (pctx->gtp_version == GTP_V0) + netdev_dbg(dev, "GTPv0-U: update tunnel id = %llx (pdp %p)\n", + pctx->u.v0.tid, pctx); + else if (pctx->gtp_version == GTP_V1) + netdev_dbg(dev, "GTPv1-U: update tunnel id = %x/%x (pdp %p)\n", + pctx->u.v1.i_tei, pctx->u.v1.o_tei, pctx); + + return pctx; + + } + + pctx = kmalloc(sizeof(*pctx), GFP_ATOMIC); + if (pctx == NULL) + return ERR_PTR(-ENOMEM); + + sock_hold(sk); + pctx->sk = sk; + pctx->dev = gtp->dev; + ipv4_pdp_fill(pctx, info); + atomic_set(&pctx->tx_seq, 0); + + switch (pctx->gtp_version) { + case GTP_V0: + /* TS 09.60: "The flow label identifies unambiguously a GTP + * flow.". We use the tid for this instead, I cannot find a + * situation in which this doesn't unambiguosly identify the + * PDP context. + */ + hash_tid = gtp0_hashfn(pctx->u.v0.tid) % gtp->hash_size; + break; + case GTP_V1: + hash_tid = gtp1u_hashfn(pctx->u.v1.i_tei) % gtp->hash_size; + break; + } + + hlist_add_head_rcu(&pctx->hlist_addr, >p->addr_hash[hash_ms]); + hlist_add_head_rcu(&pctx->hlist_tid, >p->tid_hash[hash_tid]); + + switch (pctx->gtp_version) { + case GTP_V0: + netdev_dbg(dev, "GTPv0-U: new PDP ctx id=%llx ssgn=%pI4 ms=%pI4 (pdp=%p)\n", + pctx->u.v0.tid, &pctx->peer_addr_ip4, + &pctx->ms_addr_ip4, pctx); + break; + case GTP_V1: + netdev_dbg(dev, "GTPv1-U: new PDP ctx id=%x/%x ssgn=%pI4 ms=%pI4 (pdp=%p)\n", + pctx->u.v1.i_tei, pctx->u.v1.o_tei, + &pctx->peer_addr_ip4, &pctx->ms_addr_ip4, pctx); + break; + } + + return pctx; +} + +static void pdp_context_free(struct rcu_head *head) +{ + struct pdp_ctx *pctx = container_of(head, struct pdp_ctx, rcu_head); + + sock_put(pctx->sk); + kfree(pctx); +} + +static void pdp_context_delete(struct pdp_ctx *pctx) +{ + hlist_del_rcu(&pctx->hlist_tid); + hlist_del_rcu(&pctx->hlist_addr); + call_rcu(&pctx->rcu_head, pdp_context_free); +} + +static int gtp_tunnel_notify(struct pdp_ctx *pctx, u8 cmd, gfp_t allocation); + +static int gtp_genl_new_pdp(struct sk_buff *skb, struct genl_info *info) +{ + unsigned int version; + struct pdp_ctx *pctx; + struct gtp_dev *gtp; + struct sock *sk; + int err; + + if (!info->attrs[GTPA_VERSION] || + !info->attrs[GTPA_LINK] || + !info->attrs[GTPA_PEER_ADDRESS] || + !info->attrs[GTPA_MS_ADDRESS]) + return -EINVAL; + + version = nla_get_u32(info->attrs[GTPA_VERSION]); + + switch (version) { + case GTP_V0: + if (!info->attrs[GTPA_TID] || + !info->attrs[GTPA_FLOW]) + return -EINVAL; + break; + case GTP_V1: + if (!info->attrs[GTPA_I_TEI] || + !info->attrs[GTPA_O_TEI]) + return -EINVAL; + break; + + default: + return -EINVAL; + } + + rtnl_lock(); + + gtp = gtp_find_dev(sock_net(skb->sk), info->attrs); + if (!gtp) { + err = -ENODEV; + goto out_unlock; + } + + if (version == GTP_V0) + sk = gtp->sk0; + else if (version == GTP_V1) + sk = gtp->sk1u; + else + sk = NULL; + + if (!sk) { + err = -ENODEV; + goto out_unlock; + } + + pctx = gtp_pdp_add(gtp, sk, info); + if (IS_ERR(pctx)) { + err = PTR_ERR(pctx); + } else { + gtp_tunnel_notify(pctx, GTP_CMD_NEWPDP, GFP_KERNEL); + err = 0; + } + +out_unlock: + rtnl_unlock(); + return err; +} + +static struct pdp_ctx *gtp_find_pdp_by_link(struct net *net, + struct nlattr *nla[]) +{ + struct gtp_dev *gtp; + + gtp = gtp_find_dev(net, nla); + if (!gtp) + return ERR_PTR(-ENODEV); + + if (nla[GTPA_MS_ADDRESS]) { + __be32 ip = nla_get_be32(nla[GTPA_MS_ADDRESS]); + + return ipv4_pdp_find(gtp, ip); + } else if (nla[GTPA_VERSION]) { + u32 gtp_version = nla_get_u32(nla[GTPA_VERSION]); + + if (gtp_version == GTP_V0 && nla[GTPA_TID]) + return gtp0_pdp_find(gtp, nla_get_u64(nla[GTPA_TID])); + else if (gtp_version == GTP_V1 && nla[GTPA_I_TEI]) + return gtp1_pdp_find(gtp, nla_get_u32(nla[GTPA_I_TEI])); + } + + return ERR_PTR(-EINVAL); +} + +static struct pdp_ctx *gtp_find_pdp(struct net *net, struct nlattr *nla[]) +{ + struct pdp_ctx *pctx; + + if (nla[GTPA_LINK]) + pctx = gtp_find_pdp_by_link(net, nla); + else + pctx = ERR_PTR(-EINVAL); + + if (!pctx) + pctx = ERR_PTR(-ENOENT); + + return pctx; +} + +static int gtp_genl_del_pdp(struct sk_buff *skb, struct genl_info *info) +{ + struct pdp_ctx *pctx; + int err = 0; + + if (!info->attrs[GTPA_VERSION]) + return -EINVAL; + + rcu_read_lock(); + + pctx = gtp_find_pdp(sock_net(skb->sk), info->attrs); + if (IS_ERR(pctx)) { + err = PTR_ERR(pctx); + goto out_unlock; + } + + if (pctx->gtp_version == GTP_V0) + netdev_dbg(pctx->dev, "GTPv0-U: deleting tunnel id = %llx (pdp %p)\n", + pctx->u.v0.tid, pctx); + else if (pctx->gtp_version == GTP_V1) + netdev_dbg(pctx->dev, "GTPv1-U: deleting tunnel id = %x/%x (pdp %p)\n", + pctx->u.v1.i_tei, pctx->u.v1.o_tei, pctx); + + gtp_tunnel_notify(pctx, GTP_CMD_DELPDP, GFP_ATOMIC); + pdp_context_delete(pctx); + +out_unlock: + rcu_read_unlock(); + return err; +} + +static int gtp_genl_fill_info(struct sk_buff *skb, u32 snd_portid, u32 snd_seq, + int flags, u32 type, struct pdp_ctx *pctx) +{ + void *genlh; + + genlh = genlmsg_put(skb, snd_portid, snd_seq, >p_genl_family, flags, + type); + if (genlh == NULL) + goto nlmsg_failure; + + if (nla_put_u32(skb, GTPA_VERSION, pctx->gtp_version) || + nla_put_u32(skb, GTPA_LINK, pctx->dev->ifindex) || + nla_put_be32(skb, GTPA_PEER_ADDRESS, pctx->peer_addr_ip4.s_addr) || + nla_put_be32(skb, GTPA_MS_ADDRESS, pctx->ms_addr_ip4.s_addr)) + goto nla_put_failure; + + switch (pctx->gtp_version) { + case GTP_V0: + if (nla_put_u64_64bit(skb, GTPA_TID, pctx->u.v0.tid, GTPA_PAD) || + nla_put_u16(skb, GTPA_FLOW, pctx->u.v0.flow)) + goto nla_put_failure; + break; + case GTP_V1: + if (nla_put_u32(skb, GTPA_I_TEI, pctx->u.v1.i_tei) || + nla_put_u32(skb, GTPA_O_TEI, pctx->u.v1.o_tei)) + goto nla_put_failure; + break; + } + genlmsg_end(skb, genlh); + return 0; + +nlmsg_failure: +nla_put_failure: + genlmsg_cancel(skb, genlh); + return -EMSGSIZE; +} + +static int gtp_tunnel_notify(struct pdp_ctx *pctx, u8 cmd, gfp_t allocation) +{ + struct sk_buff *msg; + int ret; + + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, allocation); + if (!msg) + return -ENOMEM; + + ret = gtp_genl_fill_info(msg, 0, 0, 0, cmd, pctx); + if (ret < 0) { + nlmsg_free(msg); + return ret; + } + + ret = genlmsg_multicast_netns(>p_genl_family, dev_net(pctx->dev), msg, + 0, GTP_GENL_MCGRP, GFP_ATOMIC); + return ret; +} + +static int gtp_genl_get_pdp(struct sk_buff *skb, struct genl_info *info) +{ + struct pdp_ctx *pctx = NULL; + struct sk_buff *skb2; + int err; + + if (!info->attrs[GTPA_VERSION]) + return -EINVAL; + + rcu_read_lock(); + + pctx = gtp_find_pdp(sock_net(skb->sk), info->attrs); + if (IS_ERR(pctx)) { + err = PTR_ERR(pctx); + goto err_unlock; + } + + skb2 = genlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC); + if (skb2 == NULL) { + err = -ENOMEM; + goto err_unlock; + } + + err = gtp_genl_fill_info(skb2, NETLINK_CB(skb).portid, info->snd_seq, + 0, info->nlhdr->nlmsg_type, pctx); + if (err < 0) + goto err_unlock_free; + + rcu_read_unlock(); + return genlmsg_unicast(genl_info_net(info), skb2, info->snd_portid); + +err_unlock_free: + kfree_skb(skb2); +err_unlock: + rcu_read_unlock(); + return err; +} + +static int gtp_genl_dump_pdp(struct sk_buff *skb, + struct netlink_callback *cb) +{ + struct gtp_dev *last_gtp = (struct gtp_dev *)cb->args[2], *gtp; + int i, j, bucket = cb->args[0], skip = cb->args[1]; + struct net *net = sock_net(skb->sk); + struct pdp_ctx *pctx; + struct gtp_net *gn; + + gn = net_generic(net, gtp_net_id); + + if (cb->args[4]) + return 0; + + rcu_read_lock(); + list_for_each_entry_rcu(gtp, &gn->gtp_dev_list, list) { + if (last_gtp && last_gtp != gtp) + continue; + else + last_gtp = NULL; + + for (i = bucket; i < gtp->hash_size; i++) { + j = 0; + hlist_for_each_entry_rcu(pctx, >p->tid_hash[i], + hlist_tid) { + if (j >= skip && + gtp_genl_fill_info(skb, + NETLINK_CB(cb->skb).portid, + cb->nlh->nlmsg_seq, + NLM_F_MULTI, + cb->nlh->nlmsg_type, pctx)) { + cb->args[0] = i; + cb->args[1] = j; + cb->args[2] = (unsigned long)gtp; + goto out; + } + j++; + } + skip = 0; + } + bucket = 0; + } + cb->args[4] = 1; +out: + rcu_read_unlock(); + return skb->len; +} + +static int gtp_genl_send_echo_req(struct sk_buff *skb, struct genl_info *info) +{ + struct sk_buff *skb_to_send; + __be32 src_ip, dst_ip; + unsigned int version; + struct gtp_dev *gtp; + struct flowi4 fl4; + struct rtable *rt; + struct sock *sk; + __be16 port; + int len; + + if (!info->attrs[GTPA_VERSION] || + !info->attrs[GTPA_LINK] || + !info->attrs[GTPA_PEER_ADDRESS] || + !info->attrs[GTPA_MS_ADDRESS]) + return -EINVAL; + + version = nla_get_u32(info->attrs[GTPA_VERSION]); + dst_ip = nla_get_be32(info->attrs[GTPA_PEER_ADDRESS]); + src_ip = nla_get_be32(info->attrs[GTPA_MS_ADDRESS]); + + gtp = gtp_find_dev(sock_net(skb->sk), info->attrs); + if (!gtp) + return -ENODEV; + + if (!gtp->sk_created) + return -EOPNOTSUPP; + if (!(gtp->dev->flags & IFF_UP)) + return -ENETDOWN; + + if (version == GTP_V0) { + struct gtp0_header *gtp0_h; + + len = LL_RESERVED_SPACE(gtp->dev) + sizeof(struct gtp0_header) + + sizeof(struct iphdr) + sizeof(struct udphdr); + + skb_to_send = netdev_alloc_skb_ip_align(gtp->dev, len); + if (!skb_to_send) + return -ENOMEM; + + sk = gtp->sk0; + port = htons(GTP0_PORT); + + gtp0_h = skb_push(skb_to_send, sizeof(struct gtp0_header)); + memset(gtp0_h, 0, sizeof(struct gtp0_header)); + gtp0_build_echo_msg(gtp0_h, GTP_ECHO_REQ); + } else if (version == GTP_V1) { + struct gtp1_header_long *gtp1u_h; + + len = LL_RESERVED_SPACE(gtp->dev) + + sizeof(struct gtp1_header_long) + + sizeof(struct iphdr) + sizeof(struct udphdr); + + skb_to_send = netdev_alloc_skb_ip_align(gtp->dev, len); + if (!skb_to_send) + return -ENOMEM; + + sk = gtp->sk1u; + port = htons(GTP1U_PORT); + + gtp1u_h = skb_push(skb_to_send, + sizeof(struct gtp1_header_long)); + memset(gtp1u_h, 0, sizeof(struct gtp1_header_long)); + gtp1u_build_echo_msg(gtp1u_h, GTP_ECHO_REQ); + } else { + return -ENODEV; + } + + rt = ip4_route_output_gtp(&fl4, sk, dst_ip, src_ip); + if (IS_ERR(rt)) { + netdev_dbg(gtp->dev, "no route for echo request to %pI4\n", + &dst_ip); + kfree_skb(skb_to_send); + return -ENODEV; + } + + udp_tunnel_xmit_skb(rt, sk, skb_to_send, + fl4.saddr, fl4.daddr, + fl4.flowi4_tos, + ip4_dst_hoplimit(&rt->dst), + 0, + port, port, + !net_eq(sock_net(sk), + dev_net(gtp->dev)), + false); + return 0; +} + +static const struct nla_policy gtp_genl_policy[GTPA_MAX + 1] = { + [GTPA_LINK] = { .type = NLA_U32, }, + [GTPA_VERSION] = { .type = NLA_U32, }, + [GTPA_TID] = { .type = NLA_U64, }, + [GTPA_PEER_ADDRESS] = { .type = NLA_U32, }, + [GTPA_MS_ADDRESS] = { .type = NLA_U32, }, + [GTPA_FLOW] = { .type = NLA_U16, }, + [GTPA_NET_NS_FD] = { .type = NLA_U32, }, + [GTPA_I_TEI] = { .type = NLA_U32, }, + [GTPA_O_TEI] = { .type = NLA_U32, }, +}; + +static const struct genl_small_ops gtp_genl_ops[] = { + { + .cmd = GTP_CMD_NEWPDP, + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .doit = gtp_genl_new_pdp, + .flags = GENL_ADMIN_PERM, + }, + { + .cmd = GTP_CMD_DELPDP, + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .doit = gtp_genl_del_pdp, + .flags = GENL_ADMIN_PERM, + }, + { + .cmd = GTP_CMD_GETPDP, + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .doit = gtp_genl_get_pdp, + .dumpit = gtp_genl_dump_pdp, + .flags = GENL_ADMIN_PERM, + }, + { + .cmd = GTP_CMD_ECHOREQ, + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .doit = gtp_genl_send_echo_req, + .flags = GENL_ADMIN_PERM, + }, +}; + +static struct genl_family gtp_genl_family __ro_after_init = { + .name = "gtp", + .version = 0, + .hdrsize = 0, + .maxattr = GTPA_MAX, + .policy = gtp_genl_policy, + .netnsok = true, + .module = THIS_MODULE, + .small_ops = gtp_genl_ops, + .n_small_ops = ARRAY_SIZE(gtp_genl_ops), + .resv_start_op = GTP_CMD_ECHOREQ + 1, + .mcgrps = gtp_genl_mcgrps, + .n_mcgrps = ARRAY_SIZE(gtp_genl_mcgrps), +}; + +static int __net_init gtp_net_init(struct net *net) +{ + struct gtp_net *gn = net_generic(net, gtp_net_id); + + INIT_LIST_HEAD(&gn->gtp_dev_list); + return 0; +} + +static void __net_exit gtp_net_exit(struct net *net) +{ + struct gtp_net *gn = net_generic(net, gtp_net_id); + struct gtp_dev *gtp; + LIST_HEAD(list); + + rtnl_lock(); + list_for_each_entry(gtp, &gn->gtp_dev_list, list) + gtp_dellink(gtp->dev, &list); + + unregister_netdevice_many(&list); + rtnl_unlock(); +} + +static struct pernet_operations gtp_net_ops = { + .init = gtp_net_init, + .exit = gtp_net_exit, + .id = >p_net_id, + .size = sizeof(struct gtp_net), +}; + +static int __init gtp_init(void) +{ + int err; + + get_random_bytes(>p_h_initval, sizeof(gtp_h_initval)); + + err = rtnl_link_register(>p_link_ops); + if (err < 0) + goto error_out; + + err = genl_register_family(>p_genl_family); + if (err < 0) + goto unreg_rtnl_link; + + err = register_pernet_subsys(>p_net_ops); + if (err < 0) + goto unreg_genl_family; + + pr_info("GTP module loaded (pdp ctx size %zd bytes)\n", + sizeof(struct pdp_ctx)); + return 0; + +unreg_genl_family: + genl_unregister_family(>p_genl_family); +unreg_rtnl_link: + rtnl_link_unregister(>p_link_ops); +error_out: + pr_err("error loading GTP module loaded\n"); + return err; +} +late_initcall(gtp_init); + +static void __exit gtp_fini(void) +{ + genl_unregister_family(>p_genl_family); + rtnl_link_unregister(>p_link_ops); + unregister_pernet_subsys(>p_net_ops); + + pr_info("GTP module unloaded\n"); +} +module_exit(gtp_fini); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Harald Welte <hwelte@sysmocom.de>"); +MODULE_DESCRIPTION("Interface driver for GTP encapsulated traffic"); +MODULE_ALIAS_RTNL_LINK("gtp"); +MODULE_ALIAS_GENL_FAMILY("gtp"); |