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packet: move vnet_hdr code to helper functions
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packet_snd and packet_rcv support virtio net headers for GSO.
Move this logic into helper functions to be able to reuse it in
tpacket_snd and tpacket_rcv.

This is a straighforward code move with one exception. Instead of
creating and passing a separate gso_type variable, reuse
vnet_hdr.gso_type after conversion from virtio to kernel gso type.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Willem de Bruijn authored and David S. Miller committed Feb 9, 2016
1 parent 5ee14e6 commit 16cc140
Showing 1 changed file with 148 additions and 113 deletions.
261 changes: 148 additions & 113 deletions net/packet/af_packet.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1960,6 +1960,64 @@ static unsigned int run_filter(struct sk_buff *skb,
return res;
}

static int __packet_rcv_vnet(const struct sk_buff *skb,
struct virtio_net_hdr *vnet_hdr)
{
*vnet_hdr = (const struct virtio_net_hdr) { 0 };

if (skb_is_gso(skb)) {
struct skb_shared_info *sinfo = skb_shinfo(skb);

/* This is a hint as to how much should be linear. */
vnet_hdr->hdr_len =
__cpu_to_virtio16(vio_le(), skb_headlen(skb));
vnet_hdr->gso_size =
__cpu_to_virtio16(vio_le(), sinfo->gso_size);

if (sinfo->gso_type & SKB_GSO_TCPV4)
vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
else if (sinfo->gso_type & SKB_GSO_TCPV6)
vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
else if (sinfo->gso_type & SKB_GSO_UDP)
vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
else if (sinfo->gso_type & SKB_GSO_FCOE)
return -EINVAL;
else
BUG();

if (sinfo->gso_type & SKB_GSO_TCP_ECN)
vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
} else
vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;

if (skb->ip_summed == CHECKSUM_PARTIAL) {
vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
vnet_hdr->csum_start = __cpu_to_virtio16(vio_le(),
skb_checksum_start_offset(skb));
vnet_hdr->csum_offset = __cpu_to_virtio16(vio_le(),
skb->csum_offset);
} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
} /* else everything is zero */

return 0;
}

static int packet_rcv_vnet(struct msghdr *msg, const struct sk_buff *skb,
size_t *len)
{
struct virtio_net_hdr vnet_hdr;

if (*len < sizeof(vnet_hdr))
return -EINVAL;
*len -= sizeof(vnet_hdr);

if (__packet_rcv_vnet(skb, &vnet_hdr))
return -EINVAL;

return memcpy_to_msg(msg, (void *)&vnet_hdr, sizeof(vnet_hdr));
}

/*
* This function makes lazy skb cloning in hope that most of packets
* are discarded by BPF.
Expand Down Expand Up @@ -2347,6 +2405,84 @@ static void tpacket_set_protocol(const struct net_device *dev,
}
}

static int __packet_snd_vnet_parse(struct virtio_net_hdr *vnet_hdr, size_t len)
{
unsigned short gso_type = 0;

if ((vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
(__virtio16_to_cpu(vio_le(), vnet_hdr->csum_start) +
__virtio16_to_cpu(vio_le(), vnet_hdr->csum_offset) + 2 >
__virtio16_to_cpu(vio_le(), vnet_hdr->hdr_len)))
vnet_hdr->hdr_len = __cpu_to_virtio16(vio_le(),
__virtio16_to_cpu(vio_le(), vnet_hdr->csum_start) +
__virtio16_to_cpu(vio_le(), vnet_hdr->csum_offset) + 2);

if (__virtio16_to_cpu(vio_le(), vnet_hdr->hdr_len) > len)
return -EINVAL;

if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
case VIRTIO_NET_HDR_GSO_TCPV4:
gso_type = SKB_GSO_TCPV4;
break;
case VIRTIO_NET_HDR_GSO_TCPV6:
gso_type = SKB_GSO_TCPV6;
break;
case VIRTIO_NET_HDR_GSO_UDP:
gso_type = SKB_GSO_UDP;
break;
default:
return -EINVAL;
}

if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
gso_type |= SKB_GSO_TCP_ECN;

if (vnet_hdr->gso_size == 0)
return -EINVAL;
}

vnet_hdr->gso_type = gso_type; /* changes type, temporary storage */
return 0;
}

static int packet_snd_vnet_parse(struct msghdr *msg, size_t *len,
struct virtio_net_hdr *vnet_hdr)
{
int n;

if (*len < sizeof(*vnet_hdr))
return -EINVAL;
*len -= sizeof(*vnet_hdr);

n = copy_from_iter(vnet_hdr, sizeof(*vnet_hdr), &msg->msg_iter);
if (n != sizeof(*vnet_hdr))
return -EFAULT;

return __packet_snd_vnet_parse(vnet_hdr, *len);
}

static int packet_snd_vnet_gso(struct sk_buff *skb,
struct virtio_net_hdr *vnet_hdr)
{
if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
u16 s = __virtio16_to_cpu(vio_le(), vnet_hdr->csum_start);
u16 o = __virtio16_to_cpu(vio_le(), vnet_hdr->csum_offset);

if (!skb_partial_csum_set(skb, s, o))
return -EINVAL;
}

skb_shinfo(skb)->gso_size =
__virtio16_to_cpu(vio_le(), vnet_hdr->gso_size);
skb_shinfo(skb)->gso_type = vnet_hdr->gso_type;

/* Header must be checked, and gso_segs computed. */
skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
skb_shinfo(skb)->gso_segs = 0;
return 0;
}

static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
void *frame, struct net_device *dev, int size_max,
__be16 proto, unsigned char *addr, int hlen)
Expand Down Expand Up @@ -2643,12 +2779,9 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
struct sockcm_cookie sockc;
struct virtio_net_hdr vnet_hdr = { 0 };
int offset = 0;
int vnet_hdr_len;
struct packet_sock *po = pkt_sk(sk);
unsigned short gso_type = 0;
int hlen, tlen;
int extra_len = 0;
ssize_t n;

/*
* Get and verify the address.
Expand Down Expand Up @@ -2686,53 +2819,9 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
if (sock->type == SOCK_RAW)
reserve = dev->hard_header_len;
if (po->has_vnet_hdr) {
vnet_hdr_len = sizeof(vnet_hdr);

err = -EINVAL;
if (len < vnet_hdr_len)
goto out_unlock;

len -= vnet_hdr_len;

err = -EFAULT;
n = copy_from_iter(&vnet_hdr, vnet_hdr_len, &msg->msg_iter);
if (n != vnet_hdr_len)
goto out_unlock;

if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
(__virtio16_to_cpu(vio_le(), vnet_hdr.csum_start) +
__virtio16_to_cpu(vio_le(), vnet_hdr.csum_offset) + 2 >
__virtio16_to_cpu(vio_le(), vnet_hdr.hdr_len)))
vnet_hdr.hdr_len = __cpu_to_virtio16(vio_le(),
__virtio16_to_cpu(vio_le(), vnet_hdr.csum_start) +
__virtio16_to_cpu(vio_le(), vnet_hdr.csum_offset) + 2);

err = -EINVAL;
if (__virtio16_to_cpu(vio_le(), vnet_hdr.hdr_len) > len)
err = packet_snd_vnet_parse(msg, &len, &vnet_hdr);
if (err)
goto out_unlock;

if (vnet_hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
switch (vnet_hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
case VIRTIO_NET_HDR_GSO_TCPV4:
gso_type = SKB_GSO_TCPV4;
break;
case VIRTIO_NET_HDR_GSO_TCPV6:
gso_type = SKB_GSO_TCPV6;
break;
case VIRTIO_NET_HDR_GSO_UDP:
gso_type = SKB_GSO_UDP;
break;
default:
goto out_unlock;
}

if (vnet_hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
gso_type |= SKB_GSO_TCP_ECN;

if (vnet_hdr.gso_size == 0)
goto out_unlock;

}
}

if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
Expand All @@ -2744,7 +2833,8 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
}

err = -EMSGSIZE;
if (!gso_type && (len > dev->mtu + reserve + VLAN_HLEN + extra_len))
if (!vnet_hdr.gso_type &&
(len > dev->mtu + reserve + VLAN_HLEN + extra_len))
goto out_unlock;

err = -ENOBUFS;
Expand Down Expand Up @@ -2775,7 +2865,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)

sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);

if (!gso_type && (len > dev->mtu + reserve + extra_len) &&
if (!vnet_hdr.gso_type && (len > dev->mtu + reserve + extra_len) &&
!packet_extra_vlan_len_allowed(dev, skb)) {
err = -EMSGSIZE;
goto out_free;
Expand All @@ -2789,24 +2879,10 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
packet_pick_tx_queue(dev, skb);

if (po->has_vnet_hdr) {
if (vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
u16 s = __virtio16_to_cpu(vio_le(), vnet_hdr.csum_start);
u16 o = __virtio16_to_cpu(vio_le(), vnet_hdr.csum_offset);
if (!skb_partial_csum_set(skb, s, o)) {
err = -EINVAL;
goto out_free;
}
}

skb_shinfo(skb)->gso_size =
__virtio16_to_cpu(vio_le(), vnet_hdr.gso_size);
skb_shinfo(skb)->gso_type = gso_type;

/* Header must be checked, and gso_segs computed. */
skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
skb_shinfo(skb)->gso_segs = 0;

len += vnet_hdr_len;
err = packet_snd_vnet_gso(skb, &vnet_hdr);
if (err)
goto out_free;
len += sizeof(vnet_hdr);
}

skb_probe_transport_header(skb, reserve);
Expand Down Expand Up @@ -3177,51 +3253,10 @@ static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
packet_rcv_has_room(pkt_sk(sk), NULL);

if (pkt_sk(sk)->has_vnet_hdr) {
struct virtio_net_hdr vnet_hdr = { 0 };

err = -EINVAL;
vnet_hdr_len = sizeof(vnet_hdr);
if (len < vnet_hdr_len)
goto out_free;

len -= vnet_hdr_len;

if (skb_is_gso(skb)) {
struct skb_shared_info *sinfo = skb_shinfo(skb);

/* This is a hint as to how much should be linear. */
vnet_hdr.hdr_len =
__cpu_to_virtio16(vio_le(), skb_headlen(skb));
vnet_hdr.gso_size =
__cpu_to_virtio16(vio_le(), sinfo->gso_size);
if (sinfo->gso_type & SKB_GSO_TCPV4)
vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
else if (sinfo->gso_type & SKB_GSO_TCPV6)
vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
else if (sinfo->gso_type & SKB_GSO_UDP)
vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
else if (sinfo->gso_type & SKB_GSO_FCOE)
goto out_free;
else
BUG();
if (sinfo->gso_type & SKB_GSO_TCP_ECN)
vnet_hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
} else
vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;

if (skb->ip_summed == CHECKSUM_PARTIAL) {
vnet_hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
vnet_hdr.csum_start = __cpu_to_virtio16(vio_le(),
skb_checksum_start_offset(skb));
vnet_hdr.csum_offset = __cpu_to_virtio16(vio_le(),
skb->csum_offset);
} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
vnet_hdr.flags = VIRTIO_NET_HDR_F_DATA_VALID;
} /* else everything is zero */

err = memcpy_to_msg(msg, (void *)&vnet_hdr, vnet_hdr_len);
if (err < 0)
err = packet_rcv_vnet(msg, skb, &len);
if (err)
goto out_free;
vnet_hdr_len = sizeof(struct virtio_net_hdr);
}

/* You lose any data beyond the buffer you gave. If it worries
Expand Down

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