gtp: unify genl_find_pdp and prepare for per socket lookup

This unifies duplicate code into a helper. It also prepares the
groundwork to add a lookup version that uses the socket to find
attached pdp contexts.

Signed-off-by: Andreas Schultz <aschultz@tpip.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/gtp.c

@@ -1037,55 +1037,67 @@ out_unlock:
 	return err;
 }
 
-static int gtp_genl_del_pdp(struct sk_buff *skb, struct genl_info *info)
+static struct pdp_ctx *gtp_find_pdp_by_link(struct net *net,
+					    struct nlattr *nla[])
 {
-	struct pdp_ctx *pctx;
 	struct gtp_dev *gtp;
-	int err = 0;
 
-	if (!info->attrs[GTPA_VERSION] ||
-	    !info->attrs[GTPA_LINK])
-		return -EINVAL;
+	gtp = gtp_find_dev(net, nla);
+	if (!gtp)
+		return ERR_PTR(-ENODEV);
 
-	rcu_read_lock();
+	if (nla[GTPA_MS_ADDRESS]) {
+		__be32 ip = nla_get_be32(nla[GTPA_MS_ADDRESS]);
 
-	gtp = gtp_find_dev(sock_net(skb->sk), info->attrs);
-	if (!gtp) {
-		err = -ENODEV;
-		goto out_unlock;
+		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]));
 	}
 
-	switch (nla_get_u32(info->attrs[GTPA_VERSION])) {
-	case GTP_V0:
-		if (!info->attrs[GTPA_TID]) {
-			err = -EINVAL;
-			goto out_unlock;
-		}
-		pctx = gtp0_pdp_find(gtp, nla_get_u64(info->attrs[GTPA_TID]));
-		break;
-	case GTP_V1:
-		if (!info->attrs[GTPA_I_TEI]) {
-			err = -EINVAL;
-			goto out_unlock;
-		}
-		pctx = gtp1_pdp_find(gtp, nla_get_u64(info->attrs[GTPA_I_TEI]));
-		break;
+	return ERR_PTR(-EINVAL);
+}
 
-	default:
-		err = -EINVAL;
-		goto out_unlock;
-	}
+static struct pdp_ctx *gtp_find_pdp(struct net *net, struct nlattr *nla[])
+{
+	struct pdp_ctx *pctx;
 
-	if (!pctx) {
-		err = -ENOENT;
+	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(gtp->dev, "GTPv0-U: deleting tunnel id = %llx (pdp %p)\n",
+		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(gtp->dev, "GTPv1-U: deleting tunnel id = %x/%x (pdp %p)\n",
+		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);
 
 	hlist_del_rcu(&pctx->hlist_tid);
@@ -1139,49 +1151,16 @@ static int gtp_genl_get_pdp(struct sk_buff *skb, struct genl_info *info)
 {
 	struct pdp_ctx *pctx = NULL;
 	struct sk_buff *skb2;
-	struct gtp_dev *gtp;
-	u32 gtp_version;
 	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:
+	if (!info->attrs[GTPA_VERSION])
 		return -EINVAL;
-	}
 
 	rcu_read_lock();
 
-	gtp = gtp_find_dev(sock_net(skb->sk), info->attrs);
-	if (!gtp) {
-		err = -ENODEV;
-		goto err_unlock;
-	}
-
-	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;
+	pctx = gtp_find_pdp(sock_net(skb->sk), info->attrs);
+	if (IS_ERR(pctx)) {
+		err = PTR_ERR(pctx);
 		goto err_unlock;
 	}