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| author |   Davide Caratti <dcaratti@redhat.com> | 2017-05-18 15:44:38 +0200 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2017-05-19 19:21:29 -0400 |
| commit | b72b5bf6a8fc9065f270ae135bbd47abb9d96790 (patch) | |
| tree | 3ef3e49136727497d5722cdd4eed3c9419661d4d /net/core/dev.c | |
| parent | skbuff: add stub to help computing crc32c on SCTP packets (diff) | |
| download | linux-dev-b72b5bf6a8fc9065f270ae135bbd47abb9d96790.tar.xz linux-dev-b72b5bf6a8fc9065f270ae135bbd47abb9d96790.zip | |
net: introduce skb_crc32c_csum_help
skb_crc32c_csum_help is like skb_checksum_help, but it is designed for
checksumming SCTP packets using crc32c (see RFC3309), provided that
libcrc32c.ko has been loaded before. In case libcrc32c is not loaded,
invoking skb_crc32c_csum_help on a skb results in one the following
printouts:
warn_crc32c_csum_update: attempt to compute crc32c without libcrc32c.ko
warn_crc32c_csum_combine: attempt to compute crc32c without libcrc32c.ko
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index acd594c56f0a..8356d5f05f89 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -143,6 +143,7 @@ #include <linux/hrtimer.h> #include <linux/netfilter_ingress.h> #include <linux/crash_dump.h> +#include <linux/sctp.h> #include "net-sysfs.h" @@ -2612,6 +2613,46 @@ out: } EXPORT_SYMBOL(skb_checksum_help); +int skb_crc32c_csum_help(struct sk_buff *skb) +{ + __le32 crc32c_csum; + int ret = 0, offset, start; + + if (skb->ip_summed != CHECKSUM_PARTIAL) + goto out; + + if (unlikely(skb_is_gso(skb))) + goto out; + + /* Before computing a checksum, we should make sure no frag could + * be modified by an external entity : checksum could be wrong. + */ + if (unlikely(skb_has_shared_frag(skb))) { + ret = __skb_linearize(skb); + if (ret) + goto out; + } + start = skb_checksum_start_offset(skb); + offset = start + offsetof(struct sctphdr, checksum); + if (WARN_ON_ONCE(offset >= skb_headlen(skb))) { + ret = -EINVAL; + goto out; + } + if (skb_cloned(skb) && + !skb_clone_writable(skb, offset + sizeof(__le32))) { + ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC); + if (ret) + goto out; + } + crc32c_csum = cpu_to_le32(~__skb_checksum(skb, start, + skb->len - start, ~(__u32)0, + crc32c_csum_stub)); + *(__le32 *)(skb->data + offset) = crc32c_csum; + skb->ip_summed = CHECKSUM_NONE; +out: + return ret; +} + __be16 skb_network_protocol(struct sk_buff *skb, int *depth) { __be16 type = skb->protocol; |