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| author | David S. Miller <davem@davemloft.net> | 2007-03-25 20:27:59 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-04-25 22:23:45 -0700 |
| commit | fc910a27839584209726537698b596576940add4 (patch) | |
| tree | e03b021dcb5046ffb1e8154f0f4d4bc72c4c1c1d /include/linux | |
| parent | ca043569390c528de4cd5ec9e07502f2bf4ecd1f (diff) | |
| download | lwn-fc910a27839584209726537698b596576940add4.tar.gz lwn-fc910a27839584209726537698b596576940add4.zip | |
[NETLINK]: Limit NLMSG_GOODSIZE to 8K.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/netlink.h | 11 | ||||
| -rw-r--r-- | include/linux/skbuff.h | 8 |
2 files changed, 14 insertions, 5 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h index 2a20f488ac1b..a9d3ad5bc80f 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -171,9 +171,16 @@ int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol); /* * skb should fit one page. This choice is good for headerless malloc. + * But we should limit to 8K so that userspace does not have to + * use enormous buffer sizes on recvmsg() calls just to avoid + * MSG_TRUNC when PAGE_SIZE is very large. */ -#define NLMSG_GOODORDER 0 -#define NLMSG_GOODSIZE (SKB_MAX_ORDER(0, NLMSG_GOODORDER)) +#if PAGE_SIZE < 8192UL +#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(PAGE_SIZE) +#else +#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(8192UL) +#endif + #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index f9441b5f8d13..30089adb2e78 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -39,9 +39,11 @@ #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \ ~(SMP_CACHE_BYTES - 1)) -#define SKB_MAX_ORDER(X, ORDER) (((PAGE_SIZE << (ORDER)) - (X) - \ - sizeof(struct skb_shared_info)) & \ - ~(SMP_CACHE_BYTES - 1)) +#define SKB_WITH_OVERHEAD(X) \ + (((X) - sizeof(struct skb_shared_info)) & \ + ~(SMP_CACHE_BYTES - 1)) +#define SKB_MAX_ORDER(X, ORDER) \ + SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X)) #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0)) #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2)) |