diff options
Diffstat (limited to 'net/ethernet/eth.c')
| -rw-r--r-- | net/ethernet/eth.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c index 5cebca134585..33a140e15834 100644 --- a/net/ethernet/eth.c +++ b/net/ethernet/eth.c @@ -146,6 +146,33 @@ int eth_rebuild_header(struct sk_buff *skb) EXPORT_SYMBOL(eth_rebuild_header); /** + * eth_get_headlen - determine the the length of header for an ethernet frame + * @data: pointer to start of frame + * @len: total length of frame + * + * Make a best effort attempt to pull the length for all of the headers for + * a given frame in a linear buffer. + */ +u32 eth_get_headlen(void *data, unsigned int len) +{ + const struct ethhdr *eth = (const struct ethhdr *)data; + struct flow_keys keys; + + /* this should never happen, but better safe than sorry */ + if (len < sizeof(*eth)) + return len; + + /* parse any remaining L2/L3 headers, check for L4 */ + if (!__skb_flow_dissect(NULL, &keys, data, + eth->h_proto, sizeof(*eth), len)) + return max_t(u32, keys.thoff, sizeof(*eth)); + + /* parse for any L4 headers */ + return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len); +} +EXPORT_SYMBOL(eth_get_headlen); + +/** * eth_type_trans - determine the packet's protocol ID. * @skb: received socket data * @dev: receiving network device |