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>

24 files changed, 104 insertions, 6 deletions

diff --git a/arch/alpha/include/asm/socket.h b/arch/alpha/include/asm/socket.h
index 16449d330dae..dcb221a4b5be 100644
--- a/arch/alpha/include/asm/socket.h
+++ b/arch/alpha/include/asm/socket.h
@@ -73,6 +73,9 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 /* O_NONBLOCK clashes with the bits used for socket types.  Therefore we
  * have to define SOCK_NONBLOCK to a different value here.
  */
diff --git a/arch/arm/include/asm/socket.h b/arch/arm/include/asm/socket.h
index d958c74e5260..6433cadb6ed4 100644
--- a/arch/arm/include/asm/socket.h
+++ b/arch/arm/include/asm/socket.h
@@ -66,4 +66,7 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/avr32/include/asm/socket.h b/arch/avr32/include/asm/socket.h
index 30078f98b3ab..a473f8c6a9aa 100644
--- a/arch/avr32/include/asm/socket.h
+++ b/arch/avr32/include/asm/socket.h
@@ -66,4 +66,7 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif /* __ASM_AVR32_SOCKET_H */
diff --git a/arch/cris/include/asm/socket.h b/arch/cris/include/asm/socket.h
index 048aba64600c..ae52825021af 100644
--- a/arch/cris/include/asm/socket.h
+++ b/arch/cris/include/asm/socket.h
@@ -68,6 +68,9 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif /* _ASM_SOCKET_H */
 
 
diff --git a/arch/frv/include/asm/socket.h b/arch/frv/include/asm/socket.h
index 7a361810f3cc..a5b1d7dbb205 100644
--- a/arch/frv/include/asm/socket.h
+++ b/arch/frv/include/asm/socket.h
@@ -66,5 +66,8 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif /* _ASM_SOCKET_H */
 
diff --git a/arch/h8300/include/asm/socket.h b/arch/h8300/include/asm/socket.h
index e7bbfcee5b99..ec4554e7b04b 100644
--- a/arch/h8300/include/asm/socket.h
+++ b/arch/h8300/include/asm/socket.h
@@ -66,4 +66,7 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/ia64/include/asm/socket.h b/arch/ia64/include/asm/socket.h
index ced62de9d5a9..41fc28a4a18a 100644
--- a/arch/ia64/include/asm/socket.h
+++ b/arch/ia64/include/asm/socket.h
@@ -75,4 +75,7 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif /* _ASM_IA64_SOCKET_H */
diff --git a/arch/m32r/include/asm/socket.h b/arch/m32r/include/asm/socket.h
index 696cb4c7ca4e..a15f40b52783 100644
--- a/arch/m32r/include/asm/socket.h
+++ b/arch/m32r/include/asm/socket.h
@@ -66,4 +66,7 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif /* _ASM_M32R_SOCKET_H */
diff --git a/arch/m68k/include/asm/socket.h b/arch/m68k/include/asm/socket.h
index e8b41a6775f9..d1be684edf97 100644
--- a/arch/m68k/include/asm/socket.h
+++ b/arch/m68k/include/asm/socket.h
@@ -66,4 +66,7 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/mips/include/asm/socket.h b/arch/mips/include/asm/socket.h
index 52104872e9e3..a2ed6fdad4e0 100644
--- a/arch/mips/include/asm/socket.h
+++ b/arch/mips/include/asm/socket.h
@@ -86,6 +86,9 @@ To add: #define SO_REUSEPORT 0x0200	/* Allow local address and port reuse.  */
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #ifdef __KERNEL__
 
 /** sock_type - Socket types
diff --git a/arch/mn10300/include/asm/socket.h b/arch/mn10300/include/asm/socket.h
index 013fcc51698f..820463a484b8 100644
--- a/arch/mn10300/include/asm/socket.h
+++ b/arch/mn10300/include/asm/socket.h
@@ -66,4 +66,7 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/parisc/include/asm/socket.h b/arch/parisc/include/asm/socket.h
index f717c9bec16f..1b52c2c31a7a 100644
--- a/arch/parisc/include/asm/socket.h
+++ b/arch/parisc/include/asm/socket.h
@@ -65,6 +65,10 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		0x4023
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		0x4024
+
+
 /* O_NONBLOCK clashes with the bits used for socket types.  Therefore we
  * have to define SOCK_NONBLOCK to a different value here.
  */
diff --git a/arch/powerpc/include/asm/socket.h b/arch/powerpc/include/asm/socket.h
index fe1c0b478fd7..3d5179bb122f 100644
--- a/arch/powerpc/include/asm/socket.h
+++ b/arch/powerpc/include/asm/socket.h
@@ -73,4 +73,7 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif	/* _ASM_POWERPC_SOCKET_H */
diff --git a/arch/s390/include/asm/socket.h b/arch/s390/include/asm/socket.h
index 581702fa1b0c..c91b720965c0 100644
--- a/arch/s390/include/asm/socket.h
+++ b/arch/s390/include/asm/socket.h
@@ -74,4 +74,7 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/sparc/include/asm/socket.h b/arch/sparc/include/asm/socket.h
index 68e2e2746f6f..bea1568ae4af 100644
--- a/arch/sparc/include/asm/socket.h
+++ b/arch/sparc/include/asm/socket.h
@@ -62,6 +62,10 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		0x0026
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		0x0027
+
+
 /* Security levels - as per NRL IPv6 - don't actually do anything */
 #define SO_SECURITY_AUTHENTICATION		0x5001
 #define SO_SECURITY_ENCRYPTION_TRANSPORT	0x5002
diff --git a/arch/xtensa/include/asm/socket.h b/arch/xtensa/include/asm/socket.h
index 74818b161362..e36c68184920 100644
--- a/arch/xtensa/include/asm/socket.h
+++ b/arch/xtensa/include/asm/socket.h
@@ -77,4 +77,7 @@
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
 
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif	/* _XTENSA_SOCKET_H */
diff --git a/include/asm-generic/socket.h b/include/asm-generic/socket.h
index d9aaac0c36d4..b1bea03274d5 100644
--- a/include/asm-generic/socket.h
+++ b/include/asm-generic/socket.h
@@ -68,4 +68,8 @@
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS	SO_WIFI_STATUS
 #define SO_PEEK_OFF		42
+
+/* Instruct lower device to use last 4-bytes of skb data as FCS */
+#define SO_NOFCS		43
+
 #endif /* __ASM_GENERIC_SOCKET_H */
diff --git a/include/linux/if.h b/include/linux/if.h
index 06b6ef60c821..f995c663c493 100644
--- a/include/linux/if.h
+++ b/include/linux/if.h
@@ -80,6 +80,8 @@
 					 * skbs on transmit */
 #define IFF_UNICAST_FLT	0x20000		/* Supports unicast filtering	*/
 #define IFF_TEAM_PORT	0x40000		/* device used as team port */
+#define IFF_SUPP_NOFCS	0x80000		/* device supports sending custom FCS */
+
 
 #define IF_GET_IFACE	0x0001		/* for querying only */
 #define IF_GET_PROTO	0x0002
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 0eac07c95255..f1b7d037c2c5 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1082,7 +1082,8 @@ struct net_device {
 	const struct header_ops *header_ops;
 
 	unsigned int		flags;	/* interface flags (a la BSD)	*/
-	unsigned int		priv_flags; /* Like 'flags' but invisible to userspace. */
+	unsigned int		priv_flags; /* Like 'flags' but invisible to userspace.
+					     * See if.h for definitions. */
 	unsigned short		gflags;
 	unsigned short		padded;	/* How much padding added by alloc_netdev() */
 
@@ -2650,6 +2651,11 @@ static inline int netif_is_bond_slave(struct net_device *dev)
 	return dev->flags & IFF_SLAVE && dev->priv_flags & IFF_BONDING;
 }
 
+static inline bool netif_supports_nofcs(struct net_device *dev)
+{
+	return dev->priv_flags & IFF_SUPP_NOFCS;
+}
+
 extern struct pernet_operations __net_initdata loopback_net_ops;
 
 /* Logging, debugging and troubleshooting/diagnostic helpers. */
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index c11a44ea1bf4..06a4c0fd7bef 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -361,6 +361,7 @@ typedef unsigned char *sk_buff_data_t;
  *		ports.
  *	@wifi_acked_valid: wifi_acked was set
  *	@wifi_acked: whether frame was acked on wifi or not
+ *	@no_fcs:  Request NIC to treat last 4 bytes as Ethernet FCS
  *	@dma_cookie: a cookie to one of several possible DMA operations
  *		done by skb DMA functions
  *	@secmark: security marking
@@ -459,7 +460,8 @@ struct sk_buff {
 	__u8			l4_rxhash:1;
 	__u8			wifi_acked_valid:1;
 	__u8			wifi_acked:1;
-	/* 10/12 bit hole (depending on ndisc_nodetype presence) */
+	__u8			no_fcs:1;
+	/* 9/11 bit hole (depending on ndisc_nodetype presence) */
 	kmemcheck_bitfield_end(flags2);
 
 #ifdef CONFIG_NET_DMA
diff --git a/include/net/sock.h b/include/net/sock.h
index 9c0553b9e451..ba761e7de252 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -615,6 +615,10 @@ enum sock_flags {
 	SOCK_RXQ_OVFL,
 	SOCK_ZEROCOPY, /* buffers from userspace */
 	SOCK_WIFI_STATUS, /* push wifi status to userspace */
+	SOCK_NOFCS, /* Tell NIC not to do the Ethernet FCS.
+		     * Will use last 4 bytes of packet sent from
+		     * user-space instead.
+		     */
 };
 
 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index f3a530780753..6eb656acdfe5 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -592,6 +592,7 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 	new->rxhash		= old->rxhash;
 	new->ooo_okay		= old->ooo_okay;
 	new->l4_rxhash		= old->l4_rxhash;
+	new->no_fcs		= old->no_fcs;
 #ifdef CONFIG_XFRM
 	new->sp			= secpath_get(old->sp);
 #endif
diff --git a/net/core/sock.c b/net/core/sock.c
index 19942d4bb6e6..55011cb691ad 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -799,6 +799,11 @@ set_rcvbuf:
 		else
 			ret = -EOPNOTSUPP;
 		break;
+
+	case SO_NOFCS:
+		sock_valbool_flag(sk, SOCK_NOFCS, valbool);
+		break;
+
 	default:
 		ret = -ENOPROTOOPT;
 		break;
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 2dbb32b988c4..ae2d484416dd 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1459,6 +1459,7 @@ static int packet_sendmsg_spkt(struct kiocb *iocb, struct socket *sock,
 	struct net_device *dev;
 	__be16 proto = 0;
 	int err;
+	int extra_len = 0;
 
 	/*
 	 *	Get and verify the address.
@@ -1493,8 +1494,16 @@ retry:
 	 * 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 @@ retry:
 		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 @@ retry:
 	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 @@ static int packet_snd(struct socket *sock,
 	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 @@ static int packet_snd(struct socket *sock,
 		}
 	}
 
+	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 @@ static int packet_snd(struct socket *sock,
 	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 @@ static int packet_snd(struct socket *sock,
 		len += vnet_hdr_len;
 	}
 
+	if (unlikely(extra_len == 4))
+		skb->no_fcs = 1;
+
 	/*
 	 *	Now send it
 	 */