[PATCH net-next v3] gtp: add notification mechanism

[Nicolas Dichtel]

Like all other network functions, let's notify gtp context on creation and
deletion.

Signed-off-by: Nicolas Dichtel <nicolas.dich...@6wind.com>
Tested-by: Gabriel Ganne <gabriel.ga...@6wind.com>
Acked-by: Harald Welte <lafo...@gnumonks.org>
---

v2 -> v3:
 - add ack from Harald
 - rebase on HEAD of net-next

v1 -> v2:
 - fix typo in the commit title
 - fix indentation of GTP_GENL_MCGRP

 drivers/net/gtp.c        | 58 +++++++++++++++++++++++++++++++++-------
 include/uapi/linux/gtp.h |  2 ++
 2 files changed, 51 insertions(+), 9 deletions(-)

diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index 21640a035d7d..c84a10569388 100644
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -928,8 +928,8 @@ static void ipv4_pdp_fill(struct pdp_ctx *pctx, struct 
genl_info *info)
        }
 }
 
-static int gtp_pdp_add(struct gtp_dev *gtp, struct sock *sk,
-                      struct genl_info *info)
+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;
@@ -956,12 +956,12 @@ static int gtp_pdp_add(struct gtp_dev *gtp, struct sock 
*sk,
 
        if (found) {
                if (info->nlhdr->nlmsg_flags & NLM_F_EXCL)
-                       return -EEXIST;
+                       return ERR_PTR(-EEXIST);
                if (info->nlhdr->nlmsg_flags & NLM_F_REPLACE)
-                       return -EOPNOTSUPP;
+                       return ERR_PTR(-EOPNOTSUPP);
 
                if (pctx && pctx_tid)
-                       return -EEXIST;
+                       return ERR_PTR(-EEXIST);
                if (!pctx)
                        pctx = pctx_tid;
 
@@ -974,13 +974,13 @@ static int gtp_pdp_add(struct gtp_dev *gtp, struct sock 
*sk,
                        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;
+               return pctx;
 
        }
 
        pctx = kmalloc(sizeof(*pctx), GFP_ATOMIC);
        if (pctx == NULL)
-               return -ENOMEM;
+               return ERR_PTR(-ENOMEM);
 
        sock_hold(sk);
        pctx->sk = sk;
@@ -1018,7 +1018,7 @@ static int gtp_pdp_add(struct gtp_dev *gtp, struct sock 
*sk,
                break;
        }
 
-       return 0;
+       return pctx;
 }
 
 static void pdp_context_free(struct rcu_head *head)
@@ -1036,9 +1036,12 @@ static void pdp_context_delete(struct pdp_ctx *pctx)
        call_rcu(&pctx->rcu_head, pdp_context_free);
 }
 
+static int gtp_tunnel_notify(struct pdp_ctx *pctx, u8 cmd);
+
 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;
@@ -1088,7 +1091,13 @@ static int gtp_genl_new_pdp(struct sk_buff *skb, struct 
genl_info *info)
                goto out_unlock;
        }
 
-       err = gtp_pdp_add(gtp, sk, info);
+       pctx = gtp_pdp_add(gtp, sk, info);
+       if (IS_ERR(pctx)) {
+               err = PTR_ERR(pctx);
+       } else {
+               gtp_tunnel_notify(pctx, GTP_CMD_NEWPDP);
+               err = 0;
+       }
 
 out_unlock:
        rcu_read_unlock();
@@ -1159,6 +1168,7 @@ static int gtp_genl_del_pdp(struct sk_buff *skb, struct 
genl_info *info)
                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);
        pdp_context_delete(pctx);
 
 out_unlock:
@@ -1168,6 +1178,14 @@ static int gtp_genl_del_pdp(struct sk_buff *skb, struct 
genl_info *info)
 
 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 int gtp_genl_fill_info(struct sk_buff *skb, u32 snd_portid, u32 snd_seq,
                              int flags, u32 type, struct pdp_ctx *pctx)
 {
@@ -1204,6 +1222,26 @@ static int gtp_genl_fill_info(struct sk_buff *skb, u32 
snd_portid, u32 snd_seq,
        return -EMSGSIZE;
 }
 
+static int gtp_tunnel_notify(struct pdp_ctx *pctx, u8 cmd)
+{
+       struct sk_buff *msg;
+       int ret;
+
+       msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+       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(&gtp_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;
@@ -1334,6 +1372,8 @@ static struct genl_family gtp_genl_family __ro_after_init 
= {
        .module         = THIS_MODULE,
        .ops            = gtp_genl_ops,
        .n_ops          = ARRAY_SIZE(gtp_genl_ops),
+       .mcgrps         = gtp_genl_mcgrps,
+       .n_mcgrps       = ARRAY_SIZE(gtp_genl_mcgrps),
 };
 
 static int __net_init gtp_net_init(struct net *net)
diff --git a/include/uapi/linux/gtp.h b/include/uapi/linux/gtp.h
index c7d66755d212..79f9191bbb24 100644
--- a/include/uapi/linux/gtp.h
+++ b/include/uapi/linux/gtp.h
@@ -2,6 +2,8 @@
 #ifndef _UAPI_LINUX_GTP_H_
 #define _UAPI_LINUX_GTP_H_
 
+#define GTP_GENL_MCGRP_NAME    "gtp"
+
 enum gtp_genl_cmds {
        GTP_CMD_NEWPDP,
        GTP_CMD_DELPDP,
-- 
2.26.2