[PATCH AUTOSEL 5.15 24/43] tipc: add tipc_bearer_min_mtu to calculate min mtu

Sasha Levin
2023-05-25T18:47:33Z

From: Xin Long <lucien.xin@gmail.com>

[ 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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/tipc/bearer.c | 13 +++++++++++++
net/tipc/bearer.h | 3 +++
net/tipc/udp_media.c | 5 +++--
3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index b0ad61b4b1013..897fc8fc08a0b 100644
--- 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 57c6a1a719e24..483f90958857e 100644
--- 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 c2bb818704c8f..0a85244fd6188 100644
--- 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 {
--
2.39.2