[PATCH v4 net-next 08/12] gtp: Call function to update path mtu

[Tom Herbert]

Replace mtu handling with call to __iptunnel_update_pmtu.

Signed-off-by: Tom Herbert <t...@quantonium.net>
---
 drivers/net/gtp.c | 36 ++++++------------------------------
 1 file changed, 6 insertions(+), 30 deletions(-)

diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index a6e2e0a1f424..bbb08f8849d3 100644
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -53,6 +53,7 @@ struct pdp_ctx {
                } v1;
        } u;
        u8                      gtp_version;
+       u8                      hlen;
        u16                     af;
 
        struct in_addr          ms_addr_ip4;
@@ -467,8 +468,6 @@ static int gtp_build_skb_ip4(struct sk_buff *skb, struct 
net_device *dev,
        struct iphdr *iph;
        struct sock *sk;
        __be32 saddr;
-       __be16 df;
-       int mtu;
 
        /* Read the IP destination address and resolve the PDP context.
         * Prepend PDP header with TEI/TID from PDP ctx.
@@ -514,37 +513,12 @@ static int gtp_build_skb_ip4(struct sk_buff *skb, struct 
net_device *dev,
 
        skb_dst_drop(skb);
 
-       /* This is similar to tnl_update_pmtu(). */
-       df = iph->frag_off;
-       if (df) {
-               mtu = dst_mtu(&rt->dst) - dev->hard_header_len -
-                       sizeof(struct iphdr) - sizeof(struct udphdr);
-               switch (pctx->gtp_version) {
-               case GTP_V0:
-                       mtu -= sizeof(struct gtp0_header);
-                       break;
-               case GTP_V1:
-                       mtu -= sizeof(struct gtp1_header);
-                       break;
-               }
-       } else {
-               mtu = dst_mtu(&rt->dst);
-       }
-
-       rt->dst.ops->update_pmtu(&rt->dst, NULL, skb, mtu);
-
-       if (!skb_is_gso(skb) && (iph->frag_off & htons(IP_DF)) &&
-           mtu < ntohs(iph->tot_len)) {
-               netdev_dbg(dev, "packet too big, fragmentation needed\n");
-               memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
-               icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
-                         htonl(mtu));
-               goto err_rt;
-       }
-
        gtp_set_pktinfo_ipv4(pktinfo, sk, iph, pctx, rt, &fl4, dev);
        gtp_push_header(skb, pktinfo);
 
+       __iptunnel_update_pmtu(dev, skb, &rt->dst, !!iph->frag_off, iph,
+                              pctx->hlen, pctx->peer_addr_ip4.s_addr);
+
        return 0;
 err_rt:
        ip_rt_put(rt);
@@ -915,10 +889,12 @@ static void ipv4_pdp_fill(struct pdp_ctx *pctx, struct 
genl_info *info)
                 */
                pctx->u.v0.tid = nla_get_u64(info->attrs[GTPA_TID]);
                pctx->u.v0.flow = nla_get_u16(info->attrs[GTPA_FLOW]);
+               pctx->hlen = sizeof(struct udphdr) + sizeof(struct gtp0_header);
                break;
        case GTP_V1:
                pctx->u.v1.i_tei = nla_get_u32(info->attrs[GTPA_I_TEI]);
                pctx->u.v1.o_tei = nla_get_u32(info->attrs[GTPA_O_TEI]);
+               pctx->hlen = sizeof(struct udphdr) + sizeof(struct gtp1_header);
                break;
        default:
                break;
-- 
2.11.0