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authorPaul Chavent <Paul.Chavent@onera.fr>2012-11-07 00:10:47 +0100
committerDavid S. Miller <davem@davemloft.net>2012-11-08 00:54:30 +0100
commit5920cd3a41f1aefc30e9ce86384fc2fe9f5fe0c0 (patch)
treececc965a19e1ffe6957d8dcf2e55566562f93e0c /net/packet/af_packet.c
parentnet: fec: reduce spin lock time in fec_ptp_adjfreq (diff)
downloadlinux-5920cd3a41f1aefc30e9ce86384fc2fe9f5fe0c0.tar.xz
linux-5920cd3a41f1aefc30e9ce86384fc2fe9f5fe0c0.zip
packet: tx_ring: allow the user to choose tx data offset
The tx data offset of packet mmap tx ring used to be : (TPACKET2_HDRLEN - sizeof(struct sockaddr_ll)) The problem is that, with SOCK_RAW socket, the payload (14 bytes after the beginning of the user data) is misaligned. This patch allows to let the user gives an offset for it's tx data if he desires. Set sock option PACKET_TX_HAS_OFF to 1, then specify in each frame of your tx ring tp_net for SOCK_DGRAM, or tp_mac for SOCK_RAW. Signed-off-by: Paul Chavent <paul.chavent@onera.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet/af_packet.c')
-rw-r--r--net/packet/af_packet.c46
1 files changed, 45 insertions, 1 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 9034f52659b5..f262dbfc7f06 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;
}