Buffer packets with sequence numbers in GTP header. (#132)

* Buffer packets with sequence numbers in GTP header. * add comments * Update the position of GTP5G_BUFFER_SEQ_NUMBER. --------- Co-authored-by: ycchen <[email protected]>
free5gc · Jan 14, 2025 · 83306b0 · 83306b0
1 parent 623ad6e
commit 83306b0
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Showing 2 changed files with 16 additions and 4 deletions.
diff --git a/include/encap.h b/include/encap.h
@@ -26,6 +26,7 @@ enum gtp5g_buffer_attrs {
     GTP5G_BUFFER_ID,
     GTP5G_BUFFER_SEID,
     GTP5G_BUFFER_ACTION,
+    GTP5G_BUFFER_SEQ_NUMBER,
 
     /* Add newly supported feature ON ABOVE
      * for compatability with older version of

diff --git a/src/gtpu/encap.c b/src/gtpu/encap.c
@@ -381,6 +381,8 @@ static int gtp5g_buf_skb_encap(struct sk_buff *skb, struct net_device *dev,
             GTP5G_ERR(dev, "Failed to pull GTP-U and UDP headers\n");
             return PKT_DROPPED;
         }
+        // Increment the sequence number for the packet
+        far->seq_number++;
 
         if (pdr_addr_is_netlink(pdr)) {
             if (netlink_send(pdr, far, skb, dev_net(dev), NULL, 0) < 0) {
@@ -414,10 +416,11 @@ static int netlink_send(struct pdr *pdr, struct far *far, struct sk_buff *skb_in
         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
     } else {
         skb = genlmsg_new(
-            nla_total_size_64bit(8) +
-                nla_total_size(2) +
-                nla_total_size(2) +
-                nla_total_size(skb_in->len),
+            nla_total_size_64bit(8) + // SEID
+                nla_total_size(2) + // PDR ID
+                nla_total_size(2) + // Action
+                nla_total_size(2) + // Sequence Num
+                nla_total_size(skb_in->len), // Buff Pkt Size
             GFP_ATOMIC);
     }
 
@@ -461,6 +464,12 @@ static int netlink_send(struct pdr *pdr, struct far *far, struct sk_buff *skb_in
             return err;
         }
 
+        err = nla_put_u16(skb, GTP5G_BUFFER_SEQ_NUMBER, far->seq_number);
+        if (err != 0) {
+            nlmsg_free(skb);
+            return err;
+        }
+
         attr = nla_reserve(skb, GTP5G_BUFFER_PACKET, skb_in->len);
         if (!attr) {
             nlmsg_free(skb);
@@ -1022,6 +1031,8 @@ static int gtp5g_fwd_skb_ipv4(struct sk_buff *skb,
 static int gtp5g_buf_skb_ipv4(struct sk_buff *skb, struct net_device *dev,
     struct pdr *pdr, struct far *far)
 {
+    // Increment the sequence number for the packet
+    far->seq_number++;
     if (pdr_addr_is_netlink(pdr)) {
         if (netlink_send(pdr, far, skb, dev_net(dev), NULL, 0) < 0) {
             GTP5G_ERR(dev, "Failed to send skb to netlink socket PDR(%u)", pdr->id);