gtp: working xmit path of gtp0
It includes lots of pr_info messages, still in very early stage, but it already transmit packets that look like GTP. Set IFF_NOARP flag in device to disable ARP resolution in gtp0, the actual device doing is the real one behind it. This patch also move code to gtp*_push_header headers.
This commit is contained in:
Pablo Neira Ayuso
parent
1350e5f734
commit
a155b2f03a
181
gtp.c
181
gtp.c
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@ -386,8 +386,10 @@ static int gtp_dev_init(struct net_device *dev)
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{
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struct gtp_instance *gti = netdev_priv(dev);
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dev->flags = IFF_NOARP;
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gti->dev = dev;
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eth_hw_addr_random(dev);
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memset(&dev->broadcast[0], 0xff, 6);
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dev->qdisc_tx_busylock = >p_eth_tx_busylock;
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@ -413,75 +415,121 @@ ip4_route_output_gtp(struct net *net, struct flowi4 *fl4,
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return ip_route_output_key(net, fl4);
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}
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static inline void
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gtp0_push_header(struct sk_buff *skb, struct pdp_ctx *pctx, int payload_len)
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{
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struct gtp0_header *gtp0;
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/* ensure there is sufficient headroom */
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skb_cow(skb, sizeof(*gtp0) + IP_UDP_LEN);
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gtp0 = (struct gtp0_header *) skb_push(skb, sizeof(*gtp0));
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gtp0->flags = 0;
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gtp0->type = GTP_TPDU;
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gtp0->length = payload_len;
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gtp0->seq = atomic_inc_return(&pctx->tx_seq) % 0xffff;
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gtp0->flow = pctx->flow;
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gtp0->number = 0xFF;
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gtp0->spare[0] = gtp0->spare[1] = gtp0->spare[2] = 0;
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gtp0->tid = pctx->tid;
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}
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static inline void
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gtp1u_push_header(struct sk_buff *skb, struct pdp_ctx *pctx, int payload_len)
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{
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struct gtp1u_header *gtp1u;
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/* ensure there is sufficient headroom */
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skb_cow(skb, sizeof(*gtp1u) + IP_UDP_LEN);
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gtp1u = (struct gtp1u_header *) skb_push(skb, sizeof(*gtp1u));
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gtp1u->flags = (1 << 5) | 0x10; /* V1, GTP-non-prime */
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gtp1u->type = GTP_TPDU;
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gtp1u->length = payload_len;
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gtp1u->tid = pctx->tid;
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}
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static netdev_tx_t gtp_dev_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct gtp_instance *gti = netdev_priv(dev);
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struct pdp_ctx *pctx;
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struct pdp_ctx *pctx = NULL;
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struct pcpu_tstats *tstats;
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struct iphdr *old_iph, *iph;
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struct udphdr *uh;
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unsigned int payload_len;
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int df, mtu;
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int df, mtu, err;
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struct rtable *rt = NULL;
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struct flowi4 fl4;
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struct net_device *tdev;
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struct inet_sock *inet;
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/* XXX */
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return NETDEV_TX_OK;
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/* UDP socket not initialized, skip */
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if (!gti->sock0) {
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pr_info("xmit: no socket / need cfg, skipping\n");
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return NETDEV_TX_OK;
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}
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inet = inet_sk(gti->sock0->sk);
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/* read the IP desination address and resolve the PDP context.
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* Prepend PDP header with TEI/TID from PDP ctx */
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rcu_read_lock_bh();
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if (skb->protocol == htons(ETH_P_IP)) {
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struct iphdr *iph = ip_hdr(skb);
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rcu_read_lock_bh();
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pctx = ipv4_pdp_find(gti, iph->daddr);
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} else if (skb->protocol == htons(ETH_P_IPV6)) {
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struct ipv6hdr *iph6 = ipv6_hdr(skb);
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rcu_read_lock_bh();
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pctx = ipv6_pdp_find(gti, &iph6->daddr);
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} else
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}
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if (!pctx) {
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rcu_read_unlock_bh();
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pr_info("no pdp ctx found, skipping\n");
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return NETDEV_TX_OK;
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}
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pr_info("found pdp ctx %p\n", pctx);
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/* Obtain route for the new encapsulated GTP packet */
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rt = ip4_route_output_gtp(dev_net(dev), &fl4, pctx->sgsn_addr.ip4,
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inet->inet_saddr, 0,
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gti->real_dev->ifindex);
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if (IS_ERR(rt)) {
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pr_info("no rt found, skipping\n");
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dev->stats.tx_carrier_errors++;
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goto tx_error;
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}
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tdev = rt->dst.dev;
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/* There is a routing loop */
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if (tdev == dev) {
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pr_info("rt loop, skipping\n");
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ip_rt_put(rt);
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dev->stats.collisions++;
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goto tx_error;
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}
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/* FIXME: does this include IP+UDP but not Eth header? */
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payload_len = skb->len;
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if (pctx->gtp_version == 0) {
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struct gtp0_header *gtp0;
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/* ensure there is sufficient headroom */
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skb_cow(skb, sizeof(*gtp0) + IP_UDP_LEN);
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gtp0 = (struct gtp0_header *) skb_push(skb, sizeof(*gtp0));
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gtp0->flags = 0;
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gtp0->type = GTP_TPDU;
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gtp0->length = payload_len;
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gtp0->seq = atomic_inc_return(&pctx->tx_seq) % 0xffff;
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gtp0->flow = pctx->flow;
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gtp0->number = 0xFF;
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gtp0->spare[0] = gtp0->spare[1] = gtp0->spare[2] = 0;
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gtp0->tid = pctx->tid;
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} else if (pctx->gtp_version == 1) {
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struct gtp1u_header *gtp1u;
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/* ensure there is sufficient headroom */
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skb_cow(skb, sizeof(*gtp1u) + IP_UDP_LEN);
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gtp1u = (struct gtp1u_header *) skb_push(skb, sizeof(*gtp1u));
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gtp1u->flags = (1 << 5) | 0x10; /* V1, GTP-non-prime */
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gtp1u->type = GTP_TPDU;
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gtp1u->length = payload_len;
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gtp1u->tid = pctx->tid;
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} else {
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rcu_read_unlock_bh();
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return NETDEV_TX_OK;
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/* Pushing GTP header */
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pr_info("pushing gtp header\n");
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switch (pctx->gtp_version) {
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case GTP_V0:
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gtp0_push_header(skb, pctx, payload_len);
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break;
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case GTP_V1:
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gtp1u_push_header(skb, pctx, payload_len);
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break;
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default:
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/* Should not happen */
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goto out;
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}
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old_iph = ip_hdr(skb);
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pr_info("pushing UDP/IP header\n");
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/* new UDP and IP header in front of GTP header */
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skb_push(skb, sizeof(struct udphdr));
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skb_reset_transport_header(skb);
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skb_push(skb, sizeof(struct iphdr));
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@ -492,31 +540,6 @@ static netdev_tx_t gtp_dev_xmit(struct sk_buff *skb, struct net_device *dev)
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skb_dst_drop(skb);
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skb_dst_set(skb, &rt->dst);
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/* XXX */
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rt = ip4_route_output_gtp(dev_net(dev), &fl4,
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0, 0, 0, 0);
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/*
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pctx->remote_u...,
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gtpi->gtp0_addr,
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old_iph->tos,
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FIXME_link);
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ip4_route_output_gtp(struct net *net, struct flowi4 *fl4,
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__be32 daddr, __be32 saddr, __u8 tos, int oif)
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*/
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if (IS_ERR(rt)) {
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dev->stats.tx_carrier_errors++;
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goto tx_error;
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}
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tdev = rt->dst.dev;
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if (tdev == dev) {
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ip_rt_put(rt);
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dev->stats.collisions++;
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goto tx_error;
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}
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df = old_iph->frag_off;
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if (df)
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// XXX: tunnel->hlen: it depends on GTP0 / GTP1
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@ -554,24 +577,36 @@ ip4_route_output_gtp(struct net *net, struct flowi4 *fl4,
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iph->saddr = fl4.saddr;
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iph->ttl = ip4_dst_hoplimit(&rt->dst);
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pr_info("gtp -> IP src: %pI4 dst: %pI4\n", &iph->saddr, &iph->daddr);
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uh = udp_hdr(skb);
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if (pctx->gtp_version == 0)
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uh->source = uh->dest = GTP0_PORT;
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uh->source = uh->dest = htons(GTP0_PORT);
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else
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uh->source = uh->dest = GTP1U_PORT;
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uh->source = uh->dest = htons(GTP1U_PORT);
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uh->len = sizeof(struct udphdr) + payload_len;
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uh->len = htons(sizeof(struct udphdr) + payload_len);
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pr_info("gtp -> UDP src: %u dst: %u (len %u)\n",
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ntohs(uh->source), ntohs(uh->dest), ntohs(uh->len));
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rcu_read_unlock_bh();
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nf_reset(skb);
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tstats = this_cpu_ptr(dev->tstats);
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/* XXX update stats? */
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// __IPTUNNEL_XMIT(tstats, &dev->stats);
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tstats = this_cpu_ptr(dev->tstats);
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err = ip_local_out(skb);
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if (unlikely(net_xmit_eval(err)))
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pr_info("error in ip_local_out\n");
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return NETDEV_TX_OK;
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out:
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rcu_read_unlock_bh();
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return NETDEV_TX_OK;
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tx_error:
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rcu_read_unlock_bh();
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pr_info("no route to reach destination\n");
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dev->stats.tx_errors++;
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dev_kfree_skb(skb);
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return NETDEV_TX_OK;
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@ -633,13 +668,13 @@ static int gtp_newlink(struct net *src_net, struct net_device *dev,
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else if (dev->mtu > real_dev->mtu)
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return -EINVAL;
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gti = netdev_priv(dev);
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gti->real_dev = real_dev;
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err = register_netdevice(dev);
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if (err < 0)
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goto err1;
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gti = netdev_priv(dev);
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gti->dev = dev;
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gti->real_dev = real_dev;
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list_add_rcu(>i->list, >p_instance_list);
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pr_info("registered new %s interface\n", dev->name);
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