From 5948ed297eefe927628e43b5142ccde691a130fd Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 4 Feb 2022 13:11:45 +0100 Subject: [PATCH] netfilter: ctnetlink: use dump structure instead of raw args netlink_dump structure has a union of 'long args[6]' and a context buffer as scratch space. Convert ctnetlink to use a structure, its easier to read than the raw 'args' usage which comes with no type checks and no readable names. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_netlink.c | 36 ++++++++++++++++++---------- 1 file changed, 24 insertions(+), 12 deletions(-) diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index ac438370f94a..3d9f9ee50294 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -58,6 +58,12 @@ MODULE_LICENSE("GPL"); +struct ctnetlink_list_dump_ctx { + struct nf_conn *last; + unsigned int cpu; + bool done; +}; + static int ctnetlink_dump_tuples_proto(struct sk_buff *skb, const struct nf_conntrack_tuple *tuple, const struct nf_conntrack_l4proto *l4proto) @@ -1694,14 +1700,18 @@ static int ctnetlink_get_conntrack(struct sk_buff *skb, static int ctnetlink_done_list(struct netlink_callback *cb) { - if (cb->args[1]) - nf_ct_put((struct nf_conn *)cb->args[1]); + struct ctnetlink_list_dump_ctx *ctx = (void *)cb->ctx; + + if (ctx->last) + nf_ct_put(ctx->last); + return 0; } static int ctnetlink_dump_list(struct sk_buff *skb, struct netlink_callback *cb, bool dying) { + struct ctnetlink_list_dump_ctx *ctx = (void *)cb->ctx; struct nf_conn *ct, *last; struct nf_conntrack_tuple_hash *h; struct hlist_nulls_node *n; @@ -1712,12 +1722,12 @@ ctnetlink_dump_list(struct sk_buff *skb, struct netlink_callback *cb, bool dying struct hlist_nulls_head *list; struct net *net = sock_net(skb->sk); - if (cb->args[2]) + if (ctx->done) return 0; - last = (struct nf_conn *)cb->args[1]; + last = ctx->last; - for (cpu = cb->args[0]; cpu < nr_cpu_ids; cpu++) { + for (cpu = ctx->cpu; cpu < nr_cpu_ids; cpu++) { struct ct_pcpu *pcpu; if (!cpu_possible(cpu)) @@ -1731,10 +1741,10 @@ ctnetlink_dump_list(struct sk_buff *skb, struct netlink_callback *cb, bool dying ct = nf_ct_tuplehash_to_ctrack(h); if (l3proto && nf_ct_l3num(ct) != l3proto) continue; - if (cb->args[1]) { + if (ctx->last) { if (ct != last) continue; - cb->args[1] = 0; + ctx->last = NULL; } /* We can't dump extension info for the unconfirmed @@ -1751,19 +1761,19 @@ ctnetlink_dump_list(struct sk_buff *skb, struct netlink_callback *cb, bool dying if (res < 0) { if (!refcount_inc_not_zero(&ct->ct_general.use)) continue; - cb->args[0] = cpu; - cb->args[1] = (unsigned long)ct; + ctx->cpu = cpu; + ctx->last = ct; spin_unlock_bh(&pcpu->lock); goto out; } } - if (cb->args[1]) { - cb->args[1] = 0; + if (ctx->last) { + ctx->last = NULL; goto restart; } spin_unlock_bh(&pcpu->lock); } - cb->args[2] = 1; + ctx->done = true; out: if (last) nf_ct_put(last); @@ -3877,6 +3887,8 @@ static int __init ctnetlink_init(void) { int ret; + BUILD_BUG_ON(sizeof(struct ctnetlink_list_dump_ctx) > sizeof_field(struct netlink_callback, ctx)); + ret = nfnetlink_subsys_register(&ctnl_subsys); if (ret < 0) { pr_err("ctnetlink_init: cannot register with nfnetlink.\n");