From 03292745b02d1166e2a215504407e096b8427be5 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 29 Jun 2012 06:15:22 +0000 Subject: netlink: add nlk->netlink_bind hook for module auto-loading This patch adds a hook in the binding path of netlink. This is used by ctnetlink to allow module autoloading for the case in which one user executes: conntrack -E So far, this resulted in nfnetlink loaded, but not nf_conntrack_netlink. I have received in the past many complains on this behaviour. Signed-off-by: Pablo Neira Ayuso Signed-off-by: David S. Miller --- include/linux/netlink.h | 1 + net/netfilter/nfnetlink.c | 29 +++++++++++++++++++++++++++++ net/netlink/af_netlink.c | 19 +++++++++++++++++++ 3 files changed, 49 insertions(+) diff --git a/include/linux/netlink.h b/include/linux/netlink.h index 6085e4919cb3..f74dd133788f 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -179,6 +179,7 @@ struct netlink_kernel_cfg { unsigned int groups; void (*input)(struct sk_buff *skb); struct mutex *cb_mutex; + void (*bind)(int group); }; extern struct sock *netlink_kernel_create(struct net *net, int unit, diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c index 700e4616a098..5a2132b97fe9 100644 --- a/net/netfilter/nfnetlink.c +++ b/net/netfilter/nfnetlink.c @@ -39,6 +39,15 @@ static char __initdata nfversion[] = "0.30"; static const struct nfnetlink_subsystem __rcu *subsys_table[NFNL_SUBSYS_COUNT]; static DEFINE_MUTEX(nfnl_mutex); +static const int nfnl_group2type[NFNLGRP_MAX+1] = { + [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK, + [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK, + [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK, + [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP, + [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP, + [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP, +}; + void nfnl_lock(void) { mutex_lock(&nfnl_mutex); @@ -200,12 +209,32 @@ static void nfnetlink_rcv(struct sk_buff *skb) netlink_rcv_skb(skb, &nfnetlink_rcv_msg); } +#ifdef CONFIG_MODULES +static void nfnetlink_bind(int group) +{ + const struct nfnetlink_subsystem *ss; + int type = nfnl_group2type[group]; + + rcu_read_lock(); + ss = nfnetlink_get_subsys(type); + if (!ss) { + rcu_read_unlock(); + request_module("nfnetlink-subsys-%d", type); + return; + } + rcu_read_unlock(); +} +#endif + static int __net_init nfnetlink_net_init(struct net *net) { struct sock *nfnl; struct netlink_kernel_cfg cfg = { .groups = NFNLGRP_MAX, .input = nfnetlink_rcv, +#ifdef CONFIG_MODULES + .bind = nfnetlink_bind, +#endif }; nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, THIS_MODULE, &cfg); diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 43a124feaad8..5463969da45b 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -80,6 +80,7 @@ struct netlink_sock { struct mutex *cb_mutex; struct mutex cb_def_mutex; void (*netlink_rcv)(struct sk_buff *skb); + void (*netlink_bind)(int group); struct module *module; }; @@ -124,6 +125,7 @@ struct netlink_table { unsigned int groups; struct mutex *cb_mutex; struct module *module; + void (*bind)(int group); int registered; }; @@ -444,6 +446,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol, struct module *module = NULL; struct mutex *cb_mutex; struct netlink_sock *nlk; + void (*bind)(int group); int err = 0; sock->state = SS_UNCONNECTED; @@ -468,6 +471,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol, else err = -EPROTONOSUPPORT; cb_mutex = nl_table[protocol].cb_mutex; + bind = nl_table[protocol].bind; netlink_unlock_table(); if (err < 0) @@ -483,6 +487,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol, nlk = nlk_sk(sock->sk); nlk->module = module; + nlk->netlink_bind = bind; out: return err; @@ -683,6 +688,15 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr, netlink_update_listeners(sk); netlink_table_ungrab(); + if (nlk->netlink_bind && nlk->groups[0]) { + int i; + + for (i=0; ingroups; i++) { + if (test_bit(i, nlk->groups)) + nlk->netlink_bind(i); + } + } + return 0; } @@ -1239,6 +1253,10 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname, netlink_update_socket_mc(nlk, val, optname == NETLINK_ADD_MEMBERSHIP); netlink_table_ungrab(); + + if (nlk->netlink_bind) + nlk->netlink_bind(val); + err = 0; break; } @@ -1559,6 +1577,7 @@ netlink_kernel_create(struct net *net, int unit, rcu_assign_pointer(nl_table[unit].listeners, listeners); nl_table[unit].cb_mutex = cb_mutex; nl_table[unit].module = module; + nl_table[unit].bind = cfg ? cfg->bind : NULL; nl_table[unit].registered = 1; } else { kfree(listeners); -- cgit v1.2.3