tipc: add tipc_bearer_min_mtu to calculate min mtu

[ Upstream commit 3ae6d66b605be604644d4bb5708a7ffd9cf1abe8 ]

As different media may requires different min mtu, and even the
same media with different net family requires different min mtu,
add tipc_bearer_min_mtu() to calculate min mtu accordingly.

This API will be used to check the new mtu when doing the link
mtu negotiation in the next patch.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: 56077b56cd3f ("tipc: do not update mtu if msg_max is too small in mtu negotiation")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index b0ad61b4b1013aedc179e1373a3561a49c941c94..897fc8fc08a0b8635594c8b35d38f80016428f68 100644 (file)
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -541,6 +541,19 @@ int tipc_bearer_mtu(struct net *net, u32 bearer_id)
        return mtu;
 }
 
+int tipc_bearer_min_mtu(struct net *net, u32 bearer_id)
+{
+       int mtu = TIPC_MIN_BEARER_MTU;
+       struct tipc_bearer *b;
+
+       rcu_read_lock();
+       b = bearer_get(net, bearer_id);
+       if (b)
+               mtu += b->encap_hlen;
+       rcu_read_unlock();
+       return mtu;
+}
+
 /* tipc_bearer_xmit_skb - sends buffer to destination over bearer
  */
 void tipc_bearer_xmit_skb(struct net *net, u32 bearer_id,

diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index 57c6a1a719e243157f91d2b6aa1f9e9e63298a3a..483f90958857ec35def01247794b2e0b3c534a5d 100644 (file)
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -146,6 +146,7 @@ struct tipc_media {
  * @identity: array index of this bearer within TIPC bearer array
  * @disc: ptr to link setup request
  * @net_plane: network plane ('A' through 'H') currently associated with bearer
+ * @encap_hlen: encap headers length
  * @up: bearer up flag (bit 0)
  * @refcnt: tipc_bearer reference counter
  *
@@ -170,6 +171,7 @@ struct tipc_bearer {
        u32 identity;
        struct tipc_discoverer *disc;
        char net_plane;
+       u16 encap_hlen;
        unsigned long up;
        refcount_t refcnt;
 };
@@ -232,6 +234,7 @@ int tipc_bearer_setup(void);
 void tipc_bearer_cleanup(void);
 void tipc_bearer_stop(struct net *net);
 int tipc_bearer_mtu(struct net *net, u32 bearer_id);
+int tipc_bearer_min_mtu(struct net *net, u32 bearer_id);
 bool tipc_bearer_bcast_support(struct net *net, u32 bearer_id);
 void tipc_bearer_xmit_skb(struct net *net, u32 bearer_id,
                          struct sk_buff *skb,

diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index c2bb818704c8ff19c03030816857e4eb06a020bf..0a85244fd61885aca6dd72a8bb54ba7678dff319 100644 (file)
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -738,8 +738,8 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
                        udp_conf.local_ip.s_addr = local.ipv4.s_addr;
                udp_conf.use_udp_checksums = false;
                ub->ifindex = dev->ifindex;
-               if (tipc_mtu_bad(dev, sizeof(struct iphdr) +
-                                     sizeof(struct udphdr))) {
+               b->encap_hlen = sizeof(struct iphdr) + sizeof(struct udphdr);
+               if (tipc_mtu_bad(dev, b->encap_hlen)) {
                        err = -EINVAL;
                        goto err;
                }
@@ -760,6 +760,7 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
                else
                        udp_conf.local_ip6 = local.ipv6;
                ub->ifindex = dev->ifindex;
+               b->encap_hlen = sizeof(struct ipv6hdr) + sizeof(struct udphdr);
                b->mtu = 1280;
 #endif
        } else {