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| author | Sven Eckelmann <sven@narfation.org> | 2012-10-17 23:10:39 +0400 |
|---|---|---|
| committer | Antonio Quartulli <ordex@autistici.org> | 2012-11-21 15:35:41 +0400 |
| commit | 95a066d82c422c812c10bfd4de01225b1714fa45 (patch) | |
| tree | e040f780728ea700af9d2df22e28b9188f586071 | |
| parent | 60d8cce7c53f188d99cb01a0a013cf3544f35e29 (diff) | |
| download | linux-95a066d82c422c812c10bfd4de01225b1714fa45.tar.xz | |
batman-adv: Add function to calculate crc32c for the skb payload
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
| -rw-r--r-- | net/batman-adv/Kconfig | 1 | ||||
| -rw-r--r-- | net/batman-adv/main.c | 34 | ||||
| -rw-r--r-- | net/batman-adv/main.h | 1 |
3 files changed, 36 insertions, 0 deletions
diff --git a/net/batman-adv/Kconfig b/net/batman-adv/Kconfig index 250e0b58109c..8d8afb134b3a 100644 --- a/net/batman-adv/Kconfig +++ b/net/batman-adv/Kconfig @@ -6,6 +6,7 @@ config BATMAN_ADV tristate "B.A.T.M.A.N. Advanced Meshing Protocol" depends on NET select CRC16 + select LIBCRC32C default n help B.A.T.M.A.N. (better approach to mobile ad-hoc networking) is diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c index dc33a0c484a4..f65a222b7b83 100644 --- a/net/batman-adv/main.c +++ b/net/batman-adv/main.c @@ -17,6 +17,8 @@ * 02110-1301, USA */ +#include <linux/crc32c.h> +#include <linux/highmem.h> #include "main.h" #include "sysfs.h" #include "debugfs.h" @@ -420,6 +422,38 @@ int batadv_algo_seq_print_text(struct seq_file *seq, void *offset) return 0; } +/** + * batadv_skb_crc32 - calculate CRC32 of the whole packet and skip bytes in + * the header + * @skb: skb pointing to fragmented socket buffers + * @payload_ptr: Pointer to position inside the head buffer of the skb + * marking the start of the data to be CRC'ed + * + * payload_ptr must always point to an address in the skb head buffer and not to + * a fragment. + */ +__be32 batadv_skb_crc32(struct sk_buff *skb, u8 *payload_ptr) +{ + u32 crc = 0; + unsigned int from; + unsigned int to = skb->len; + struct skb_seq_state st; + const u8 *data; + unsigned int len; + unsigned int consumed = 0; + + from = (unsigned int)(payload_ptr - skb->data); + + skb_prepare_seq_read(skb, from, to, &st); + while ((len = skb_seq_read(consumed, &data, &st)) != 0) { + crc = crc32c(crc, data, len); + consumed += len; + } + skb_abort_seq_read(&st); + + return htonl(crc); +} + static int batadv_param_set_ra(const char *val, const struct kernel_param *kp) { struct batadv_algo_ops *bat_algo_ops; diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h index 8f149bb66817..ce5e5b96ebee 100644 --- a/net/batman-adv/main.h +++ b/net/batman-adv/main.h @@ -174,6 +174,7 @@ void batadv_recv_handler_unregister(uint8_t packet_type); int batadv_algo_register(struct batadv_algo_ops *bat_algo_ops); int batadv_algo_select(struct batadv_priv *bat_priv, char *name); int batadv_algo_seq_print_text(struct seq_file *seq, void *offset); +__be32 batadv_skb_crc32(struct sk_buff *skb, u8 *payload_ptr); /** * enum batadv_dbg_level - available log levels |