net: Add framework to allow sending packets with customized CRC.
This is useful for testing RX handling of frames with bad
CRCs.
Requires driver support to actually put the packet on the
wire properly.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 2dbb32b..ae2d484 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1459,6 +1459,7 @@
struct net_device *dev;
__be16 proto = 0;
int err;
+ int extra_len = 0;
/*
* Get and verify the address.
@@ -1493,8 +1494,16 @@
* raw protocol and you must do your own fragmentation at this level.
*/
+ if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
+ if (!netif_supports_nofcs(dev)) {
+ err = -EPROTONOSUPPORT;
+ goto out_unlock;
+ }
+ extra_len = 4; /* We're doing our own CRC */
+ }
+
err = -EMSGSIZE;
- if (len > dev->mtu + dev->hard_header_len + VLAN_HLEN)
+ if (len > dev->mtu + dev->hard_header_len + VLAN_HLEN + extra_len)
goto out_unlock;
if (!skb) {
@@ -1526,7 +1535,7 @@
goto retry;
}
- if (len > (dev->mtu + dev->hard_header_len)) {
+ if (len > (dev->mtu + dev->hard_header_len + extra_len)) {
/* Earlier code assumed this would be a VLAN pkt,
* double-check this now that we have the actual
* packet in hand.
@@ -1548,6 +1557,9 @@
if (err < 0)
goto out_unlock;
+ if (unlikely(extra_len == 4))
+ skb->no_fcs = 1;
+
dev_queue_xmit(skb);
rcu_read_unlock();
return len;
@@ -2209,6 +2221,7 @@
struct packet_sock *po = pkt_sk(sk);
unsigned short gso_type = 0;
int hlen, tlen;
+ int extra_len = 0;
/*
* Get and verify the address.
@@ -2288,8 +2301,16 @@
}
}
+ if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
+ if (!netif_supports_nofcs(dev)) {
+ err = -EPROTONOSUPPORT;
+ goto out_unlock;
+ }
+ extra_len = 4; /* We're doing our own CRC */
+ }
+
err = -EMSGSIZE;
- if (!gso_type && (len > dev->mtu + reserve + VLAN_HLEN))
+ if (!gso_type && (len > dev->mtu + reserve + VLAN_HLEN + extra_len))
goto out_unlock;
err = -ENOBUFS;
@@ -2315,7 +2336,7 @@
if (err < 0)
goto out_free;
- if (!gso_type && (len > dev->mtu + reserve)) {
+ if (!gso_type && (len > dev->mtu + reserve + extra_len)) {
/* Earlier code assumed this would be a VLAN pkt,
* double-check this now that we have the actual
* packet in hand.
@@ -2353,6 +2374,9 @@
len += vnet_hdr_len;
}
+ if (unlikely(extra_len == 4))
+ skb->no_fcs = 1;
+
/*
* Now send it
*/
