diff options
Diffstat (limited to 'drivers/net/gtp.c')
| -rw-r--r-- | drivers/net/gtp.c | 1375 |
1 files changed, 1375 insertions, 0 deletions
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c new file mode 100644 index 000000000..4e976a0d5 --- /dev/null +++ b/drivers/net/gtp.c @@ -0,0 +1,1375 @@ +/* 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> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/version.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 { + u64 tid; + 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 sgsn_addr_ip4; + + atomic_t tx_seq; + struct rcu_head rcu_head; +}; + +/* One instance of the GTP device. */ +struct gtp_dev { + struct list_head list; + + struct socket *sock0; + struct socket *sock1u; + + struct net *net; + struct net_device *dev; + + unsigned int hash_size; + struct hlist_head *tid_hash; + struct hlist_head *addr_hash; +}; + +static int gtp_net_id __read_mostly; + +struct gtp_net { + struct list_head gtp_dev_list; +}; + +static u32 gtp_h_initval; + +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_src_ms_ipv4(struct sk_buff *skb, struct pdp_ctx *pctx, + unsigned int hdrlen) +{ + struct iphdr *iph; + + if (!pskb_may_pull(skb, hdrlen + sizeof(struct iphdr))) + return false; + + iph = (struct iphdr *)(skb->data + hdrlen + sizeof(struct iphdr)); + + return iph->saddr != pctx->ms_addr_ip4.s_addr; +} + +/* Check if the inner IP source address in this packet is assigned to any + * existing mobile subscriber. + */ +static bool gtp_check_src_ms(struct sk_buff *skb, struct pdp_ctx *pctx, + unsigned int hdrlen) +{ + switch (ntohs(skb->protocol)) { + case ETH_P_IP: + return gtp_check_src_ms_ipv4(skb, pctx, hdrlen); + } + return false; +} + +/* 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, + bool xnet) +{ + unsigned int hdrlen = sizeof(struct udphdr) + + sizeof(struct gtp0_header); + struct gtp0_header *gtp0; + struct pdp_ctx *pctx; + int ret = 0; + + 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 (gtp0->type != GTP_TPDU) + return 1; + + rcu_read_lock(); + 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); + ret = -1; + goto out_rcu; + } + + if (!gtp_check_src_ms(skb, pctx, hdrlen)) { + netdev_dbg(gtp->dev, "No PDP ctx for this MS\n"); + ret = -1; + goto out_rcu; + } + rcu_read_unlock(); + + /* Get rid of the GTP + UDP headers. */ + return iptunnel_pull_header(skb, hdrlen, skb->protocol, xnet); +out_rcu: + rcu_read_unlock(); + return ret; +} + +static int gtp1u_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb, + bool xnet) +{ + unsigned int hdrlen = sizeof(struct udphdr) + + sizeof(struct gtp1_header); + struct gtp1_header *gtp1; + struct pdp_ctx *pctx; + int ret = 0; + + 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 (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)); + + rcu_read_lock(); + pctx = gtp1_pdp_find(gtp, ntohl(gtp1->tid)); + if (!pctx) { + netdev_dbg(gtp->dev, "No PDP ctx to decap skb=%p\n", skb); + ret = -1; + goto out_rcu; + } + + if (!gtp_check_src_ms(skb, pctx, hdrlen)) { + netdev_dbg(gtp->dev, "No PDP ctx for this MS\n"); + ret = -1; + goto out_rcu; + } + rcu_read_unlock(); + + /* Get rid of the GTP + UDP headers. */ + return iptunnel_pull_header(skb, hdrlen, skb->protocol, xnet); +out_rcu: + rcu_read_unlock(); + return ret; +} + +static void gtp_encap_disable(struct gtp_dev *gtp) +{ + if (gtp->sock0 && gtp->sock0->sk) { + udp_sk(gtp->sock0->sk)->encap_type = 0; + rcu_assign_sk_user_data(gtp->sock0->sk, NULL); + } + if (gtp->sock1u && gtp->sock1u->sk) { + udp_sk(gtp->sock1u->sk)->encap_type = 0; + rcu_assign_sk_user_data(gtp->sock1u->sk, NULL); + } + + gtp->sock0 = NULL; + gtp->sock1u = NULL; +} + +static void gtp_encap_destroy(struct sock *sk) +{ + struct gtp_dev *gtp; + + gtp = rcu_dereference_sk_user_data(sk); + if (gtp) + gtp_encap_disable(gtp); +} + +/* 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 pcpu_sw_netstats *stats; + struct gtp_dev *gtp; + bool xnet; + int ret; + + gtp = rcu_dereference_sk_user_data(sk); + if (!gtp) + return 1; + + netdev_dbg(gtp->dev, "encap_recv sk=%p\n", sk); + + xnet = !net_eq(gtp->net, dev_net(gtp->dev)); + + switch (udp_sk(sk)->encap_type) { + case UDP_ENCAP_GTP0: + netdev_dbg(gtp->dev, "received GTP0 packet\n"); + ret = gtp0_udp_encap_recv(gtp, skb, xnet); + break; + case UDP_ENCAP_GTP1U: + netdev_dbg(gtp->dev, "received GTP1U packet\n"); + ret = gtp1u_udp_encap_recv(gtp, skb, xnet); + break; + default: + ret = -1; /* Shouldn't happen. */ + } + + switch (ret) { + case 1: + netdev_dbg(gtp->dev, "pass up to the process\n"); + return 1; + case 0: + netdev_dbg(gtp->dev, "forwarding packet from GGSN to uplink\n"); + break; + case -1: + netdev_dbg(gtp->dev, "GTP packet has been dropped\n"); + kfree_skb(skb); + return 0; + } + + /* 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->dev = gtp->dev; + + stats = this_cpu_ptr(gtp->dev->tstats); + u64_stats_update_begin(&stats->syncp); + stats->rx_packets++; + stats->rx_bytes += skb->len; + u64_stats_update_end(&stats->syncp); + + netif_rx(skb); + + return 0; +} + +static int gtp_dev_init(struct net_device *dev) +{ + struct gtp_dev *gtp = netdev_priv(dev); + + gtp->dev = dev; + + dev->tstats = alloc_percpu(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 struct rtable *ip4_route_output_gtp(struct net *net, struct flowi4 *fl4, + const struct sock *sk, __be32 daddr) +{ + memset(fl4, 0, sizeof(*fl4)); + fl4->flowi4_oif = sk->sk_bound_dev_if; + fl4->daddr = daddr; + fl4->saddr = inet_sk(sk)->inet_saddr; + fl4->flowi4_tos = RT_CONN_FLAGS(sk); + fl4->flowi4_proto = sk->sk_protocol; + + return ip_route_output_key(net, fl4); +} + +static inline void gtp0_push_header(struct sk_buff *skb, struct pdp_ctx *pctx) +{ + int payload_len = skb->len; + struct gtp0_header *gtp0; + + gtp0 = (struct gtp0_header *) 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 = (struct gtp1_header *) skb_push(skb, sizeof(*gtp1)); + + /* Bits 8 7 6 5 4 3 2 1 + * +--+--+--+--+--+--+--+--+ + * |version |PT| 1| E| S|PN| + * +--+--+--+--+--+--+--+--+ + * 0 0 1 1 1 0 0 0 + */ + gtp1->flags = 0x38; /* v1, GTP-non-prime. */ + gtp1->type = GTP_TPDU; + gtp1->length = htons(payload_len); + gtp1->tid = htonl(pctx->u.v1.o_tei); + + /* TODO: Suppport 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; + struct sock *sk; + __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); + 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); + + switch (pctx->gtp_version) { + case GTP_V0: + if (gtp->sock0) + sk = gtp->sock0->sk; + else + sk = NULL; + break; + case GTP_V1: + if (gtp->sock1u) + sk = gtp->sock1u->sk; + else + sk = NULL; + break; + default: + return -ENOENT; + } + + if (!sk) { + netdev_dbg(dev, "no userspace socket is available, skip\n"); + return -ENOENT; + } + + rt = ip4_route_output_gtp(sock_net(sk), &fl4, gtp->sock0->sk, + pctx->sgsn_addr_ip4.s_addr); + if (IS_ERR(rt)) { + netdev_dbg(dev, "no route to SSGN %pI4\n", + &pctx->sgsn_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->sgsn_addr_ip4.s_addr); + dev->stats.collisions++; + goto err_rt; + } + + skb_dst_drop(skb); + + /* 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); + } + + rt->dst.ops->update_pmtu(&rt->dst, NULL, skb, mtu); + + if (!skb_is_gso(skb) && (iph->frag_off & htons(IP_DF)) && + mtu < ntohs(iph->tot_len)) { + netdev_dbg(dev, "packet too big, fragmentation needed\n"); + memset(IPCB(skb), 0, sizeof(*IPCB(skb))); + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, + htonl(mtu)); + goto err_rt; + } + + gtp_set_pktinfo_ipv4(pktinfo, 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), + htons(IP_DF), + pktinfo.gtph_port, pktinfo.gtph_port, + true, 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 = ip_tunnel_get_stats64, +}; + +static void gtp_link_setup(struct net_device *dev) +{ + dev->netdev_ops = >p_netdev_ops; + dev->destructor = free_netdev; + + dev->hard_header_len = 0; + dev->addr_len = 0; + + /* 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); + + /* Assume largest header, ie. GTPv0. */ + dev->needed_headroom = LL_MAX_HEADER + + sizeof(struct iphdr) + + sizeof(struct udphdr) + + sizeof(struct gtp0_header); +} + +static int gtp_hashtable_new(struct gtp_dev *gtp, int hsize); +static void gtp_hashtable_free(struct gtp_dev *gtp); +static int gtp_encap_enable(struct net_device *dev, struct gtp_dev *gtp, + int fd_gtp0, int fd_gtp1, struct net *src_net); + +static int gtp_newlink(struct net *src_net, struct net_device *dev, + struct nlattr *tb[], struct nlattr *data[]) +{ + int hashsize, err, fd0, fd1; + struct gtp_dev *gtp; + struct gtp_net *gn; + + if (!data[IFLA_GTP_FD0] || !data[IFLA_GTP_FD1]) + return -EINVAL; + + gtp = netdev_priv(dev); + + fd0 = nla_get_u32(data[IFLA_GTP_FD0]); + fd1 = nla_get_u32(data[IFLA_GTP_FD1]); + + err = gtp_encap_enable(dev, gtp, fd0, fd1, src_net); + if (err < 0) + goto out_err; + + if (!data[IFLA_GTP_PDP_HASHSIZE]) + hashsize = 1024; + else + hashsize = nla_get_u32(data[IFLA_GTP_PDP_HASHSIZE]); + + err = gtp_hashtable_new(gtp, hashsize); + if (err < 0) + goto out_encap; + + err = register_netdevice(dev); + if (err < 0) { + netdev_dbg(dev, "failed to register new netdev %d\n", err); + goto out_hashtable; + } + + gn = net_generic(dev_net(dev), gtp_net_id); + list_add_rcu(>p->list, &gn->gtp_dev_list); + + netdev_dbg(dev, "registered new GTP interface\n"); + + return 0; + +out_hashtable: + gtp_hashtable_free(gtp); +out_encap: + gtp_encap_disable(gtp); +out_err: + return err; +} + +static void gtp_dellink(struct net_device *dev, struct list_head *head) +{ + struct gtp_dev *gtp = netdev_priv(dev); + + gtp_encap_disable(gtp); + gtp_hashtable_free(gtp); + 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 }, +}; + +static int gtp_validate(struct nlattr *tb[], struct nlattr *data[]) +{ + 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 */ +} + +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; + + 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 struct net *gtp_genl_get_net(struct net *src_net, struct nlattr *tb[]) +{ + struct net *net; + + /* Examine the link attributes and figure out which network namespace + * we are talking about. + */ + if (tb[GTPA_NET_NS_FD]) + net = get_net_ns_by_fd(nla_get_u32(tb[GTPA_NET_NS_FD])); + else + net = get_net(src_net); + + return net; +} + +static int gtp_hashtable_new(struct gtp_dev *gtp, int hsize) +{ + int i; + + gtp->addr_hash = kmalloc(sizeof(struct hlist_head) * hsize, GFP_KERNEL); + if (gtp->addr_hash == NULL) + return -ENOMEM; + + gtp->tid_hash = kmalloc(sizeof(struct hlist_head) * hsize, GFP_KERNEL); + 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 void gtp_hashtable_free(struct gtp_dev *gtp) +{ + 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) { + hlist_del_rcu(&pctx->hlist_tid); + hlist_del_rcu(&pctx->hlist_addr); + kfree_rcu(pctx, rcu_head); + } + } + synchronize_rcu(); + kfree(gtp->addr_hash); + kfree(gtp->tid_hash); +} + +static int gtp_encap_enable(struct net_device *dev, struct gtp_dev *gtp, + int fd_gtp0, int fd_gtp1, struct net *src_net) +{ + struct udp_tunnel_sock_cfg tuncfg = {NULL}; + struct socket *sock0, *sock1u; + int err; + + netdev_dbg(dev, "enable gtp on %d, %d\n", fd_gtp0, fd_gtp1); + + sock0 = sockfd_lookup(fd_gtp0, &err); + if (sock0 == NULL) { + netdev_dbg(dev, "socket fd=%d not found (gtp0)\n", fd_gtp0); + return -ENOENT; + } + + if (sock0->sk->sk_protocol != IPPROTO_UDP) { + netdev_dbg(dev, "socket fd=%d not UDP\n", fd_gtp0); + err = -EINVAL; + goto err1; + } + + sock1u = sockfd_lookup(fd_gtp1, &err); + if (sock1u == NULL) { + netdev_dbg(dev, "socket fd=%d not found (gtp1u)\n", fd_gtp1); + err = -ENOENT; + goto err1; + } + + if (sock1u->sk->sk_protocol != IPPROTO_UDP) { + netdev_dbg(dev, "socket fd=%d not UDP\n", fd_gtp1); + err = -EINVAL; + goto err2; + } + + netdev_dbg(dev, "enable gtp on %p, %p\n", sock0, sock1u); + + gtp->sock0 = sock0; + gtp->sock1u = sock1u; + gtp->net = src_net; + + tuncfg.sk_user_data = gtp; + tuncfg.encap_rcv = gtp_encap_recv; + tuncfg.encap_destroy = gtp_encap_destroy; + + tuncfg.encap_type = UDP_ENCAP_GTP0; + setup_udp_tunnel_sock(sock_net(gtp->sock0->sk), gtp->sock0, &tuncfg); + + tuncfg.encap_type = UDP_ENCAP_GTP1U; + setup_udp_tunnel_sock(sock_net(gtp->sock1u->sk), gtp->sock1u, &tuncfg); + + err = 0; +err2: + sockfd_put(sock1u); +err1: + sockfd_put(sock0); + return err; +} + +static struct net_device *gtp_find_dev(struct net *net, int ifindex) +{ + struct gtp_net *gn = net_generic(net, gtp_net_id); + struct gtp_dev *gtp; + + list_for_each_entry_rcu(gtp, &gn->gtp_dev_list, list) { + if (ifindex == gtp->dev->ifindex) + return gtp->dev; + } + return NULL; +} + +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->sgsn_addr_ip4.s_addr = + nla_get_be32(info->attrs[GTPA_SGSN_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 int ipv4_pdp_add(struct net_device *dev, struct genl_info *info) +{ + struct gtp_dev *gtp = netdev_priv(dev); + u32 hash_ms, hash_tid = 0; + struct pdp_ctx *pctx; + 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; + + hlist_for_each_entry_rcu(pctx, >p->addr_hash[hash_ms], hlist_addr) { + if (pctx->ms_addr_ip4.s_addr == ms_addr) { + found = true; + break; + } + } + + if (found) { + if (info->nlhdr->nlmsg_flags & NLM_F_EXCL) + return -EEXIST; + if (info->nlhdr->nlmsg_flags & NLM_F_REPLACE) + return -EOPNOTSUPP; + + 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 0; + + } + + pctx = kmalloc(sizeof(struct pdp_ctx), GFP_KERNEL); + if (pctx == NULL) + return -ENOMEM; + + 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->sgsn_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->sgsn_addr_ip4, &pctx->ms_addr_ip4, pctx); + break; + } + + return 0; +} + +static int gtp_genl_new_pdp(struct sk_buff *skb, struct genl_info *info) +{ + struct net_device *dev; + struct net *net; + + if (!info->attrs[GTPA_VERSION] || + !info->attrs[GTPA_LINK] || + !info->attrs[GTPA_SGSN_ADDRESS] || + !info->attrs[GTPA_MS_ADDRESS]) + return -EINVAL; + + switch (nla_get_u32(info->attrs[GTPA_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; + } + + net = gtp_genl_get_net(sock_net(skb->sk), info->attrs); + if (IS_ERR(net)) + return PTR_ERR(net); + + /* Check if there's an existing gtpX device to configure */ + dev = gtp_find_dev(net, nla_get_u32(info->attrs[GTPA_LINK])); + if (dev == NULL) { + put_net(net); + return -ENODEV; + } + put_net(net); + + return ipv4_pdp_add(dev, info); +} + +static int gtp_genl_del_pdp(struct sk_buff *skb, struct genl_info *info) +{ + struct net_device *dev; + struct pdp_ctx *pctx; + struct gtp_dev *gtp; + struct net *net; + + if (!info->attrs[GTPA_VERSION] || + !info->attrs[GTPA_LINK]) + return -EINVAL; + + net = gtp_genl_get_net(sock_net(skb->sk), info->attrs); + if (IS_ERR(net)) + return PTR_ERR(net); + + /* Check if there's an existing gtpX device to configure */ + dev = gtp_find_dev(net, nla_get_u32(info->attrs[GTPA_LINK])); + if (dev == NULL) { + put_net(net); + return -ENODEV; + } + put_net(net); + + gtp = netdev_priv(dev); + + switch (nla_get_u32(info->attrs[GTPA_VERSION])) { + case GTP_V0: + if (!info->attrs[GTPA_TID]) + return -EINVAL; + pctx = gtp0_pdp_find(gtp, nla_get_u64(info->attrs[GTPA_TID])); + break; + case GTP_V1: + if (!info->attrs[GTPA_I_TEI]) + return -EINVAL; + pctx = gtp1_pdp_find(gtp, nla_get_u64(info->attrs[GTPA_I_TEI])); + break; + + default: + return -EINVAL; + } + + if (pctx == NULL) + return -ENOENT; + + if (pctx->gtp_version == GTP_V0) + netdev_dbg(dev, "GTPv0-U: deleting tunnel id = %llx (pdp %p)\n", + pctx->u.v0.tid, pctx); + else if (pctx->gtp_version == GTP_V1) + netdev_dbg(dev, "GTPv1-U: deleting tunnel id = %x/%x (pdp %p)\n", + pctx->u.v1.i_tei, pctx->u.v1.o_tei, pctx); + + hlist_del_rcu(&pctx->hlist_tid); + hlist_del_rcu(&pctx->hlist_addr); + kfree_rcu(pctx, rcu_head); + + return 0; +} + +static struct genl_family gtp_genl_family = { + .id = GENL_ID_GENERATE, + .name = "gtp", + .version = 0, + .hdrsize = 0, + .maxattr = GTPA_MAX, + .netnsok = true, +}; + +static int gtp_genl_fill_info(struct sk_buff *skb, u32 snd_portid, u32 snd_seq, + u32 type, struct pdp_ctx *pctx) +{ + void *genlh; + + genlh = genlmsg_put(skb, snd_portid, snd_seq, >p_genl_family, 0, + type); + if (genlh == NULL) + goto nlmsg_failure; + + if (nla_put_u32(skb, GTPA_VERSION, pctx->gtp_version) || + nla_put_be32(skb, GTPA_SGSN_ADDRESS, pctx->sgsn_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_genl_get_pdp(struct sk_buff *skb, struct genl_info *info) +{ + struct pdp_ctx *pctx = NULL; + struct net_device *dev; + struct sk_buff *skb2; + struct gtp_dev *gtp; + u32 gtp_version; + struct net *net; + int err; + + if (!info->attrs[GTPA_VERSION] || + !info->attrs[GTPA_LINK]) + return -EINVAL; + + gtp_version = nla_get_u32(info->attrs[GTPA_VERSION]); + switch (gtp_version) { + case GTP_V0: + case GTP_V1: + break; + default: + return -EINVAL; + } + + net = gtp_genl_get_net(sock_net(skb->sk), info->attrs); + if (IS_ERR(net)) + return PTR_ERR(net); + + /* Check if there's an existing gtpX device to configure */ + dev = gtp_find_dev(net, nla_get_u32(info->attrs[GTPA_LINK])); + if (dev == NULL) { + put_net(net); + return -ENODEV; + } + put_net(net); + + gtp = netdev_priv(dev); + + rcu_read_lock(); + if (gtp_version == GTP_V0 && + info->attrs[GTPA_TID]) { + u64 tid = nla_get_u64(info->attrs[GTPA_TID]); + + pctx = gtp0_pdp_find(gtp, tid); + } else if (gtp_version == GTP_V1 && + info->attrs[GTPA_I_TEI]) { + u32 tid = nla_get_u32(info->attrs[GTPA_I_TEI]); + + pctx = gtp1_pdp_find(gtp, tid); + } else if (info->attrs[GTPA_MS_ADDRESS]) { + __be32 ip = nla_get_be32(info->attrs[GTPA_MS_ADDRESS]); + + pctx = ipv4_pdp_find(gtp, ip); + } + + if (pctx == NULL) { + err = -ENOENT; + 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, 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; + struct net *net = sock_net(skb->sk); + struct gtp_net *gn = net_generic(net, gtp_net_id); + unsigned long tid = cb->args[1]; + int i, k = cb->args[0], ret; + struct pdp_ctx *pctx; + + if (cb->args[4]) + return 0; + + list_for_each_entry_rcu(gtp, &gn->gtp_dev_list, list) { + if (last_gtp && last_gtp != gtp) + continue; + else + last_gtp = NULL; + + for (i = k; i < gtp->hash_size; i++) { + hlist_for_each_entry_rcu(pctx, >p->tid_hash[i], hlist_tid) { + if (tid && tid != pctx->u.tid) + continue; + else + tid = 0; + + ret = gtp_genl_fill_info(skb, + NETLINK_CB(cb->skb).portid, + cb->nlh->nlmsg_seq, + cb->nlh->nlmsg_type, pctx); + if (ret < 0) { + cb->args[0] = i; + cb->args[1] = pctx->u.tid; + cb->args[2] = (unsigned long)gtp; + goto out; + } + } + } + } + cb->args[4] = 1; +out: + return skb->len; +} + +static 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_SGSN_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_ops gtp_genl_ops[] = { + { + .cmd = GTP_CMD_NEWPDP, + .doit = gtp_genl_new_pdp, + .policy = gtp_genl_policy, + .flags = GENL_ADMIN_PERM, + }, + { + .cmd = GTP_CMD_DELPDP, + .doit = gtp_genl_del_pdp, + .policy = gtp_genl_policy, + .flags = GENL_ADMIN_PERM, + }, + { + .cmd = GTP_CMD_GETPDP, + .doit = gtp_genl_get_pdp, + .dumpit = gtp_genl_dump_pdp, + .policy = gtp_genl_policy, + .flags = GENL_ADMIN_PERM, + }, +}; + +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_with_ops(>p_genl_family, gtp_genl_ops); + 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) +{ + unregister_pernet_subsys(>p_net_ops); + genl_unregister_family(>p_genl_family); + rtnl_link_unregister(>p_link_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"); |