diff options
author | Rusty Russell <rusty@rustcorp.com.au> | 2008-02-04 23:49:54 -0500 |
---|---|---|
committer | Rusty Russell <rusty@rustcorp.com.au> | 2008-02-04 07:49:56 -0500 |
commit | f35d9d8aae08940b7fdd1bb8110619da2ece6b28 (patch) | |
tree | 562d8d7a6583d0a0750ec8d996026b73e8315421 /net/core/skbuff.c | |
parent | 9135f1901ee6449dfe338adf6e40e9c2025b8150 (diff) |
virtio: Implement skb_partial_csum_set, for setting partial csums on untrusted packets.
Use it in virtio_net (replacing buggy version there), it's also going
to be used by TAP for partial csum support.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/skbuff.c')
-rw-r--r-- | net/core/skbuff.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 98420f9c4b6d..4e354221ec23 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c | |||
@@ -2461,6 +2461,34 @@ int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer) | |||
2461 | return elt; | 2461 | return elt; |
2462 | } | 2462 | } |
2463 | 2463 | ||
2464 | /** | ||
2465 | * skb_partial_csum_set - set up and verify partial csum values for packet | ||
2466 | * @skb: the skb to set | ||
2467 | * @start: the number of bytes after skb->data to start checksumming. | ||
2468 | * @off: the offset from start to place the checksum. | ||
2469 | * | ||
2470 | * For untrusted partially-checksummed packets, we need to make sure the values | ||
2471 | * for skb->csum_start and skb->csum_offset are valid so we don't oops. | ||
2472 | * | ||
2473 | * This function checks and sets those values and skb->ip_summed: if this | ||
2474 | * returns false you should drop the packet. | ||
2475 | */ | ||
2476 | bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off) | ||
2477 | { | ||
2478 | if (unlikely(start > skb->len - 2) || | ||
2479 | unlikely((int)start + off > skb->len - 2)) { | ||
2480 | if (net_ratelimit()) | ||
2481 | printk(KERN_WARNING | ||
2482 | "bad partial csum: csum=%u/%u len=%u\n", | ||
2483 | start, off, skb->len); | ||
2484 | return false; | ||
2485 | } | ||
2486 | skb->ip_summed = CHECKSUM_PARTIAL; | ||
2487 | skb->csum_start = skb_headroom(skb) + start; | ||
2488 | skb->csum_offset = off; | ||
2489 | return true; | ||
2490 | } | ||
2491 | |||
2464 | EXPORT_SYMBOL(___pskb_trim); | 2492 | EXPORT_SYMBOL(___pskb_trim); |
2465 | EXPORT_SYMBOL(__kfree_skb); | 2493 | EXPORT_SYMBOL(__kfree_skb); |
2466 | EXPORT_SYMBOL(kfree_skb); | 2494 | EXPORT_SYMBOL(kfree_skb); |
@@ -2497,3 +2525,4 @@ EXPORT_SYMBOL(skb_append_datato_frags); | |||
2497 | 2525 | ||
2498 | EXPORT_SYMBOL_GPL(skb_to_sgvec); | 2526 | EXPORT_SYMBOL_GPL(skb_to_sgvec); |
2499 | EXPORT_SYMBOL_GPL(skb_cow_data); | 2527 | EXPORT_SYMBOL_GPL(skb_cow_data); |
2528 | EXPORT_SYMBOL_GPL(skb_partial_csum_set); | ||