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| author | Eric Dumazet <edumazet@google.com> | 2012-06-12 19:30:21 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-06-13 15:57:31 -0700 |
| commit | 954fba0274058d27c7c07b5ea07c41b3b7477894 (patch) | |
| tree | 259b3fbcf79b801a8ea2c4c9401cc460aebfae62 | |
| parent | 5ee31c6898ea5537fcea160999d60dc63bc0c305 (diff) | |
| download | linux-954fba0274058d27c7c07b5ea07c41b3b7477894.tar.gz linux-954fba0274058d27c7c07b5ea07c41b3b7477894.tar.bz2 linux-954fba0274058d27c7c07b5ea07c41b3b7477894.zip | |
netpoll: fix netpoll_send_udp() bugs
Bogdan Hamciuc diagnosed and fixed following bug in netpoll_send_udp() :
"skb->len += len;" instead of "skb_put(skb, len);"
Meaning that _if_ a network driver needs to call skb_realloc_headroom(),
only packet headers would be copied, leaving garbage in the payload.
However the skb_realloc_headroom() must be avoided as much as possible
since it requires memory and netpoll tries hard to work even if memory
is exhausted (using a pool of preallocated skbs)
It appears netpoll_send_udp() reserved 16 bytes for the ethernet header,
which happens to work for typicall drivers but not all.
Right thing is to use LL_RESERVED_SPACE(dev)
(And also add dev->needed_tailroom of tailroom)
This patch combines both fixes.
Many thanks to Bogdan for raising this issue.
Reported-by: Bogdan Hamciuc <bogdan.hamciuc@freescale.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Bogdan Hamciuc <bogdan.hamciuc@freescale.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/core/netpoll.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 3d84fb9d8873..f9f40b932e4b 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -362,22 +362,23 @@ EXPORT_SYMBOL(netpoll_send_skb_on_dev); void netpoll_send_udp(struct netpoll *np, const char *msg, int len) { - int total_len, eth_len, ip_len, udp_len; + int total_len, ip_len, udp_len; struct sk_buff *skb; struct udphdr *udph; struct iphdr *iph; struct ethhdr *eth; udp_len = len + sizeof(*udph); - ip_len = eth_len = udp_len + sizeof(*iph); - total_len = eth_len + ETH_HLEN + NET_IP_ALIGN; + ip_len = udp_len + sizeof(*iph); + total_len = ip_len + LL_RESERVED_SPACE(np->dev); - skb = find_skb(np, total_len, total_len - len); + skb = find_skb(np, total_len + np->dev->needed_tailroom, + total_len - len); if (!skb) return; skb_copy_to_linear_data(skb, msg, len); - skb->len += len; + skb_put(skb, len); skb_push(skb, sizeof(*udph)); skb_reset_transport_header(skb); |