Having the socket present in context simplifies the sending logic.
It also fixes the invalid assumption that we have to use the same
sending socket for all client IP's on a specific gtp interface.

Signed-off-by: Andreas Schultz <aschu...@tpip.net>
---
 drivers/net/gtp.c | 72 ++++++++++++++++++++++++++++++-------------------------
 1 file changed, 39 insertions(+), 33 deletions(-)

diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index 68c6c9b..ff00597 100644
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -58,6 +58,8 @@ struct pdp_ctx {
        struct in_addr          ms_addr_ip4;
        struct in_addr          sgsn_addr_ip4;
 
+       struct sock             *sk;
+
        atomic_t                tx_seq;
        struct rcu_head         rcu_head;
 };
@@ -371,8 +373,9 @@ static void gtp_dev_uninit(struct net_device *dev)
        free_percpu(dev->tstats);
 }
 
-static struct rtable *ip4_route_output_gtp(struct net *net, struct flowi4 *fl4,
-                                          const struct sock *sk, __be32 daddr)
+static struct rtable *ip4_route_output_gtp(struct flowi4 *fl4,
+                                          const struct sock *sk,
+                                          __be32 daddr)
 {
        memset(fl4, 0, sizeof(*fl4));
        fl4->flowi4_oif         = sk->sk_bound_dev_if;
@@ -381,7 +384,7 @@ static struct rtable *ip4_route_output_gtp(struct net *net, 
struct flowi4 *fl4,
        fl4->flowi4_tos         = RT_CONN_FLAGS(sk);
        fl4->flowi4_proto       = sk->sk_protocol;
 
-       return ip_route_output_key(net, fl4);
+       return ip_route_output_key(sock_net(sk), fl4);
 }
 
 static inline void gtp0_push_header(struct sk_buff *skb, struct pdp_ctx *pctx)
@@ -470,7 +473,6 @@ static int gtp_build_skb_ip4(struct sk_buff *skb, struct 
net_device *dev,
        struct rtable *rt;
        struct flowi4 fl4;
        struct iphdr *iph;
-       struct sock *sk;
        __be16 df;
        int mtu;
 
@@ -486,30 +488,7 @@ static int gtp_build_skb_ip4(struct sk_buff *skb, struct 
net_device *dev,
        }
        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);
+       rt = ip4_route_output_gtp(&fl4, pctx->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);
@@ -554,7 +533,7 @@ static int gtp_build_skb_ip4(struct sk_buff *skb, struct 
net_device *dev,
                goto err_rt;
        }
 
-       gtp_set_pktinfo_ipv4(pktinfo, sk, iph, pctx, rt, &fl4, dev);
+       gtp_set_pktinfo_ipv4(pktinfo, pctx->sk, iph, pctx, rt, &fl4, dev);
        gtp_push_header(skb, pktinfo);
 
        return 0;
@@ -908,7 +887,8 @@ static void ipv4_pdp_fill(struct pdp_ctx *pctx, struct 
genl_info *info)
        }
 }
 
-static int ipv4_pdp_add(struct gtp_dev *gtp, struct genl_info *info)
+static int ipv4_pdp_add(struct gtp_dev *gtp, struct sock *sk,
+                       struct genl_info *info)
 {
        u32 hash_ms, hash_tid = 0;
        struct pdp_ctx *pctx;
@@ -948,6 +928,8 @@ static int ipv4_pdp_add(struct gtp_dev *gtp, struct 
genl_info *info)
        if (pctx == NULL)
                return -ENOMEM;
 
+       sock_hold(sk);
+       pctx->sk = sk;
        ipv4_pdp_fill(pctx, info);
        atomic_set(&pctx->tx_seq, 0);
 
@@ -984,16 +966,26 @@ static int ipv4_pdp_add(struct gtp_dev *gtp, struct 
genl_info *info)
        return 0;
 }
 
+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);
-       kfree(pctx);
+       call_rcu(&pctx->rcu_head, pdp_context_free);
 }
 
 static int gtp_genl_new_pdp(struct sk_buff *skb, struct genl_info *info)
 {
+       unsigned int version;
        struct gtp_dev *gtp;
+       struct socket *sock;
        int err;
 
        if (!info->attrs[GTPA_VERSION] ||
@@ -1002,7 +994,9 @@ static int gtp_genl_new_pdp(struct sk_buff *skb, struct 
genl_info *info)
            !info->attrs[GTPA_MS_ADDRESS])
                return -EINVAL;
 
-       switch (nla_get_u32(info->attrs[GTPA_VERSION])) {
+       version = nla_get_u32(info->attrs[GTPA_VERSION]);
+
+       switch (version) {
        case GTP_V0:
                if (!info->attrs[GTPA_TID] ||
                    !info->attrs[GTPA_FLOW])
@@ -1026,7 +1020,19 @@ static int gtp_genl_new_pdp(struct sk_buff *skb, struct 
genl_info *info)
                goto out_unlock;
        }
 
-       err = ipv4_pdp_add(gtp, info);
+       if (version == GTP_V0)
+               sock = gtp->sock0;
+       else if (version == GTP_V1)
+               sock = gtp->sock1u;
+       else
+               sock = NULL;
+
+       if (!sock || !sock->sk) {
+               err = -ENODEV;
+               goto out_unlock;
+       }
+
+       err = ipv4_pdp_add(gtp, sock->sk, info);
 
 out_unlock:
        rcu_read_unlock();
-- 
2.10.2

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