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authorEric Dumazet <eric.dumazet@gmail.com>2011-04-21 09:45:37 +0000
committerDavid S. Miller <davem@davemloft.net>2011-04-28 13:16:35 -0700
commitf6d8bd051c391c1c0458a30b2a7abcd939329259 (patch)
tree1dc4daecdeb0b42c2c6b59d7d6b41e091c11db5f /include/net/inet_sock.h
parent0a14842f5a3c0e88a1e59fac5c3025db39721f74 (diff)
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inet: add RCU protection to inet->opt
We lack proper synchronization to manipulate inet->opt ip_options Problem is ip_make_skb() calls ip_setup_cork() and ip_setup_cork() possibly makes a copy of ipc->opt (struct ip_options), without any protection against another thread manipulating inet->opt. Another thread can change inet->opt pointer and free old one under us. Use RCU to protect inet->opt (changed to inet->inet_opt). Instead of handling atomic refcounts, just copy ip_options when necessary, to avoid cache line dirtying. We cant insert an rcu_head in struct ip_options since its included in skb->cb[], so this patch is large because I had to introduce a new ip_options_rcu structure. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/inet_sock.h')
-rw-r--r--include/net/inet_sock.h14
1 files changed, 11 insertions, 3 deletions
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 7a37369f8ea3..ed2ba6eca724 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -57,7 +57,15 @@ struct ip_options {
unsigned char __data[0];
};
-#define optlength(opt) (sizeof(struct ip_options) + opt->optlen)
+struct ip_options_rcu {
+ struct rcu_head rcu;
+ struct ip_options opt;
+};
+
+struct ip_options_data {
+ struct ip_options_rcu opt;
+ char data[40];
+};
struct inet_request_sock {
struct request_sock req;
@@ -78,7 +86,7 @@ struct inet_request_sock {
acked : 1,
no_srccheck: 1;
kmemcheck_bitfield_end(flags);
- struct ip_options *opt;
+ struct ip_options_rcu *opt;
};
static inline struct inet_request_sock *inet_rsk(const struct request_sock *sk)
@@ -140,7 +148,7 @@ struct inet_sock {
__be16 inet_sport;
__u16 inet_id;
- struct ip_options *opt;
+ struct ip_options_rcu __rcu *inet_opt;
__u8 tos;
__u8 min_ttl;
__u8 mc_ttl;