diff options
| -rw-r--r-- | Documentation/networking/packet_mmap.txt | 13 | ||||
| -rw-r--r-- | include/uapi/linux/if_packet.h | 1 | ||||
| -rw-r--r-- | net/packet/af_packet.c | 46 | ||||
| -rw-r--r-- | net/packet/internal.h | 1 |
4 files changed, 60 insertions, 1 deletions
diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt index 1c08a4b..7cd879e 100644 --- a/Documentation/networking/packet_mmap.txt +++ b/Documentation/networking/packet_mmap.txt @@ -163,6 +163,19 @@ As capture, each frame contains two parts: A complete tutorial is available at: http://wiki.gnu-log.net/ +By default, the user should put data at : + frame base + TPACKET_HDRLEN - sizeof(struct sockaddr_ll) + +So, whatever you choose for the socket mode (SOCK_DGRAM or SOCK_RAW), +the beginning of the user data will be at : + frame base + TPACKET_ALIGN(sizeof(struct tpacket_hdr)) + +If you wish to put user data at a custom offset from the beginning of +the frame (for payload alignment with SOCK_RAW mode for instance) you +can set tp_net (with SOCK_DGRAM) or tp_mac (with SOCK_RAW). In order +to make this work it must be enabled previously with setsockopt() +and the PACKET_TX_HAS_OFF option. + -------------------------------------------------------------------------------- + PACKET_MMAP settings -------------------------------------------------------------------------------- diff --git a/include/uapi/linux/if_packet.h b/include/uapi/linux/if_packet.h index f379929..f9a6037 100644 --- a/include/uapi/linux/if_packet.h +++ b/include/uapi/linux/if_packet.h @@ -50,6 +50,7 @@ struct sockaddr_ll { #define PACKET_TX_TIMESTAMP 16 #define PACKET_TIMESTAMP 17 #define PACKET_FANOUT 18 +#define PACKET_TX_HAS_OFF 19 #define PACKET_FANOUT_HASH 0 #define PACKET_FANOUT_LB 1 diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 9034f52..f262dbf 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1881,7 +1881,35 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb, skb_reserve(skb, hlen); skb_reset_network_header(skb); - data = ph.raw + po->tp_hdrlen - sizeof(struct sockaddr_ll); + if (po->tp_tx_has_off) { + int off_min, off_max, off; + off_min = po->tp_hdrlen - sizeof(struct sockaddr_ll); + off_max = po->tx_ring.frame_size - tp_len; + if (sock->type == SOCK_DGRAM) { + switch (po->tp_version) { + case TPACKET_V2: + off = ph.h2->tp_net; + break; + default: + off = ph.h1->tp_net; + break; + } + } else { + switch (po->tp_version) { + case TPACKET_V2: + off = ph.h2->tp_mac; + break; + default: + off = ph.h1->tp_mac; + break; + } + } + if (unlikely((off < off_min) || (off_max < off))) + return -EINVAL; + data = ph.raw + off; + } else { + data = ph.raw + po->tp_hdrlen - sizeof(struct sockaddr_ll); + } to_write = tp_len; if (sock->type == SOCK_DGRAM) { @@ -3109,6 +3137,19 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv return fanout_add(sk, val & 0xffff, val >> 16); } + case PACKET_TX_HAS_OFF: + { + unsigned int val; + + if (optlen != sizeof(val)) + return -EINVAL; + if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) + return -EBUSY; + if (copy_from_user(&val, optval, sizeof(val))) + return -EFAULT; + po->tp_tx_has_off = !!val; + return 0; + } default: return -ENOPROTOOPT; } @@ -3200,6 +3241,9 @@ static int packet_getsockopt(struct socket *sock, int level, int optname, ((u32)po->fanout->type << 16)) : 0); break; + case PACKET_TX_HAS_OFF: + val = po->tp_tx_has_off; + break; default: return -ENOPROTOOPT; } diff --git a/net/packet/internal.h b/net/packet/internal.h index 44945f6..e84cab8 100644 --- a/net/packet/internal.h +++ b/net/packet/internal.h @@ -109,6 +109,7 @@ struct packet_sock { unsigned int tp_hdrlen; unsigned int tp_reserve; unsigned int tp_loss:1; + unsigned int tp_tx_has_off:1; unsigned int tp_tstamp; struct packet_type prot_hook ____cacheline_aligned_in_smp; }; |
