Re: [PATCH v6 1/4] udp_tunnel: add config option to bind to a device
From: Sabrina Dubroca <sd@queasysnail.net>
Date: 2018-12-01 01:40:34
2018-11-27, 14:05:42 +0100, Alexis Bauvin wrote:
quoted hunk ↗ jump to hunk
diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c index 6539ff15e9a3..dc68e15a4f72 100644 --- a/net/ipv4/udp_tunnel.c +++ b/net/ipv4/udp_tunnel.c@@ -20,6 +20,16 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg, if (err < 0) goto error; + if (cfg->bind_ifindex) { + struct net_device *dev; + + dev = __dev_get_by_index(net, cfg->bind_ifindex);
Quoting from net/core/dev.c: * [...] The device has not * had its reference counter increased so the caller must be careful * about locking. The caller must hold either the RTNL semaphore * or @dev_base_lock. */ which is the case for VXLAN (and GENEVE) during ndo_open, but I don't think other UDP tunnels (FOU, L2TP) are holding RTNL when they call udp_sock_create(). dev_get_by_index() + dev_put() should be safe. Also, I don't think it's a problem with vxlan, but this could handle the case where __dev_get_by_index returns NULL.
+ err = kernel_setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, + dev->name, strlen(dev->name) + 1); + if (err < 0) + goto error; + } + udp_addr.sin_family = AF_INET; udp_addr.sin_addr = cfg->local_ip; udp_addr.sin_port = cfg->local_udp_port;
-- Sabrina