net/smc: fix smc clc failed issue when netdevice not in init_net

If the netdevice is within a container and communicates externally
through network technologies such as VxLAN, we won't be able to find
routing information in the init_net namespace. To address this issue,
we need to add a struct net parameter to the smc_ib_find_route function.
This allow us to locate the routing information within the corresponding
net namespace, ensuring the correct completion of the SMC CLC interaction.

Fixes: e5c4744 ("net/smc: add SMC-Rv2 connection establishment")
Signed-off-by: Albert Huang <huangjie.albert@bytedance.com>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Link: https://lore.kernel.org/r/20231011074851.95280-1-huangjie.albert@bytedance.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Albert Huang

net/smc/af_smc.c

@@ -1201,6 +1201,7 @@ static int smc_connect_rdma_v2_prepare(struct smc_sock *smc,
 		(struct smc_clc_msg_accept_confirm_v2 *)aclc;
 	struct smc_clc_first_contact_ext *fce =
 		smc_get_clc_first_contact_ext(clc_v2, false);
+	struct net *net = sock_net(&smc->sk);
 	int rc;
 
 	if (!ini->first_contact_peer || aclc->hdr.version == SMC_V1)
@@ -1210,7 +1211,7 @@ static int smc_connect_rdma_v2_prepare(struct smc_sock *smc,
 		memcpy(ini->smcrv2.nexthop_mac, &aclc->r0.lcl.mac, ETH_ALEN);
 		ini->smcrv2.uses_gateway = false;
 	} else {
-		if (smc_ib_find_route(smc->clcsock->sk->sk_rcv_saddr,
+		if (smc_ib_find_route(net, smc->clcsock->sk->sk_rcv_saddr,
 				      smc_ib_gid_to_ipv4(aclc->r0.lcl.gid),
 				      ini->smcrv2.nexthop_mac,
 				      &ini->smcrv2.uses_gateway))

net/smc/smc_ib.c

@@ -193,7 +193,7 @@ bool smc_ib_port_active(struct smc_ib_device *smcibdev, u8 ibport)
 	return smcibdev->pattr[ibport - 1].state == IB_PORT_ACTIVE;
 }
 
-int smc_ib_find_route(__be32 saddr, __be32 daddr,
+int smc_ib_find_route(struct net *net, __be32 saddr, __be32 daddr,
 		      u8 nexthop_mac[], u8 *uses_gateway)
 {
 	struct neighbour *neigh = NULL;
@@ -205,7 +205,7 @@ int smc_ib_find_route(__be32 saddr, __be32 daddr,
 
 	if (daddr == cpu_to_be32(INADDR_NONE))
 		goto out;
-	rt = ip_route_output_flow(&init_net, &fl4, NULL);
+	rt = ip_route_output_flow(net, &fl4, NULL);
 	if (IS_ERR(rt))
 		goto out;
 	if (rt->rt_uses_gateway && rt->rt_gw_family != AF_INET)
@@ -235,6 +235,7 @@ static int smc_ib_determine_gid_rcu(const struct net_device *ndev,
 	if (smcrv2 && attr->gid_type == IB_GID_TYPE_ROCE_UDP_ENCAP &&
 	    smc_ib_gid_to_ipv4((u8 *)&attr->gid) != cpu_to_be32(INADDR_NONE)) {
 		struct in_device *in_dev = __in_dev_get_rcu(ndev);
+		struct net *net = dev_net(ndev);
 		const struct in_ifaddr *ifa;
 		bool subnet_match = false;
 
@@ -248,7 +249,7 @@ static int smc_ib_determine_gid_rcu(const struct net_device *ndev,
 		}
 		if (!subnet_match)
 			goto out;
-		if (smcrv2->daddr && smc_ib_find_route(smcrv2->saddr,
+		if (smcrv2->daddr && smc_ib_find_route(net, smcrv2->saddr,
 						       smcrv2->daddr,
 						       smcrv2->nexthop_mac,
 						       &smcrv2->uses_gateway))

net/smc/smc_ib.h

@@ -112,7 +112,7 @@ void smc_ib_sync_sg_for_device(struct smc_link *lnk,
 int smc_ib_determine_gid(struct smc_ib_device *smcibdev, u8 ibport,
 			 unsigned short vlan_id, u8 gid[], u8 *sgid_index,
 			 struct smc_init_info_smcrv2 *smcrv2);
-int smc_ib_find_route(__be32 saddr, __be32 daddr,
+int smc_ib_find_route(struct net *net, __be32 saddr, __be32 daddr,
 		      u8 nexthop_mac[], u8 *uses_gateway);
 bool smc_ib_is_valid_local_systemid(void);
 int smcr_nl_get_device(struct sk_buff *skb, struct netlink_callback *cb);