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ixgbe: Add support for generic Tx checksums
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This patch adds support for generic Tx checksums to the ixgbe driver.  It
turns out this is actually pretty easy after going over the datasheet as we
were doing a number of steps we didn't need to.

In order to perform a Tx checksum for an L4 header we need to fill in the
following fields in the Tx descriptor:
  MACLEN (maximum of 127), retrieved from:
		skb_network_offset()
  IPLEN  (maximum of 511), retrieved from:
		skb_checksum_start_offset() - skb_network_offset()
  TUCMD.L4T indicates offset and if checksum or crc32c, based on:
		skb->csum_offset

The added advantage to doing this is that we can support inner checksum
offloads for tunnels and MPLS while still being able to transparently
insert VLAN tags.

I also took the opportunity to clean-up many of the feature flag
configuration bits to make them a bit more consistent between drivers.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
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Alexander Duyck authored and Jeff Kirsher committed Apr 5, 2016
1 parent c7374b5 commit 49763de
Showing 1 changed file with 58 additions and 104 deletions.
162 changes: 58 additions & 104 deletions drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7202,103 +7202,61 @@ static int ixgbe_tso(struct ixgbe_ring *tx_ring,
return 1;
}

static inline bool ixgbe_ipv6_csum_is_sctp(struct sk_buff *skb)
{
unsigned int offset = 0;

ipv6_find_hdr(skb, &offset, IPPROTO_SCTP, NULL, NULL);

return offset == skb_checksum_start_offset(skb);
}

static void ixgbe_tx_csum(struct ixgbe_ring *tx_ring,
struct ixgbe_tx_buffer *first)
{
struct sk_buff *skb = first->skb;
u32 vlan_macip_lens = 0;
u32 mss_l4len_idx = 0;
u32 type_tucmd = 0;

if (skb->ip_summed != CHECKSUM_PARTIAL) {
if (!(first->tx_flags & IXGBE_TX_FLAGS_HW_VLAN) &&
!(first->tx_flags & IXGBE_TX_FLAGS_CC))
csum_failed:
if (!(first->tx_flags & (IXGBE_TX_FLAGS_HW_VLAN |
IXGBE_TX_FLAGS_CC)))
return;
vlan_macip_lens = skb_network_offset(skb) <<
IXGBE_ADVTXD_MACLEN_SHIFT;
} else {
u8 l4_hdr = 0;
union {
struct iphdr *ipv4;
struct ipv6hdr *ipv6;
u8 *raw;
} network_hdr;
union {
struct tcphdr *tcphdr;
u8 *raw;
} transport_hdr;
__be16 frag_off;

if (skb->encapsulation) {
network_hdr.raw = skb_inner_network_header(skb);
transport_hdr.raw = skb_inner_transport_header(skb);
vlan_macip_lens = skb_inner_network_offset(skb) <<
IXGBE_ADVTXD_MACLEN_SHIFT;
} else {
network_hdr.raw = skb_network_header(skb);
transport_hdr.raw = skb_transport_header(skb);
vlan_macip_lens = skb_network_offset(skb) <<
IXGBE_ADVTXD_MACLEN_SHIFT;
}
goto no_csum;
}

/* use first 4 bits to determine IP version */
switch (network_hdr.ipv4->version) {
case IPVERSION:
vlan_macip_lens |= transport_hdr.raw - network_hdr.raw;
type_tucmd |= IXGBE_ADVTXD_TUCMD_IPV4;
l4_hdr = network_hdr.ipv4->protocol;
break;
case 6:
vlan_macip_lens |= transport_hdr.raw - network_hdr.raw;
l4_hdr = network_hdr.ipv6->nexthdr;
if (likely((transport_hdr.raw - network_hdr.raw) ==
sizeof(struct ipv6hdr)))
break;
ipv6_skip_exthdr(skb, network_hdr.raw - skb->data +
sizeof(struct ipv6hdr),
&l4_hdr, &frag_off);
if (unlikely(frag_off))
l4_hdr = NEXTHDR_FRAGMENT;
break;
default:
switch (skb->csum_offset) {
case offsetof(struct tcphdr, check):
type_tucmd = IXGBE_ADVTXD_TUCMD_L4T_TCP;
/* fall through */
case offsetof(struct udphdr, check):
break;
case offsetof(struct sctphdr, checksum):
/* validate that this is actually an SCTP request */
if (((first->protocol == htons(ETH_P_IP)) &&
(ip_hdr(skb)->protocol == IPPROTO_SCTP)) ||
((first->protocol == htons(ETH_P_IPV6)) &&
ixgbe_ipv6_csum_is_sctp(skb))) {
type_tucmd = IXGBE_ADVTXD_TUCMD_L4T_SCTP;
break;
}

switch (l4_hdr) {
case IPPROTO_TCP:
type_tucmd |= IXGBE_ADVTXD_TUCMD_L4T_TCP;
mss_l4len_idx = (transport_hdr.tcphdr->doff * 4) <<
IXGBE_ADVTXD_L4LEN_SHIFT;
break;
case IPPROTO_SCTP:
type_tucmd |= IXGBE_ADVTXD_TUCMD_L4T_SCTP;
mss_l4len_idx = sizeof(struct sctphdr) <<
IXGBE_ADVTXD_L4LEN_SHIFT;
break;
case IPPROTO_UDP:
mss_l4len_idx = sizeof(struct udphdr) <<
IXGBE_ADVTXD_L4LEN_SHIFT;
break;
default:
if (unlikely(net_ratelimit())) {
dev_warn(tx_ring->dev,
"partial checksum, version=%d, l4 proto=%x\n",
network_hdr.ipv4->version, l4_hdr);
}
skb_checksum_help(skb);
goto no_csum;
}

/* update TX checksum flag */
first->tx_flags |= IXGBE_TX_FLAGS_CSUM;
/* fall through */
default:
skb_checksum_help(skb);
goto csum_failed;
}

/* update TX checksum flag */
first->tx_flags |= IXGBE_TX_FLAGS_CSUM;
vlan_macip_lens = skb_checksum_start_offset(skb) -
skb_network_offset(skb);
no_csum:
/* vlan_macip_lens: MACLEN, VLAN tag */
vlan_macip_lens |= skb_network_offset(skb) << IXGBE_ADVTXD_MACLEN_SHIFT;
vlan_macip_lens |= first->tx_flags & IXGBE_TX_FLAGS_VLAN_MASK;

ixgbe_tx_ctxtdesc(tx_ring, vlan_macip_lens, 0,
type_tucmd, mss_l4len_idx);
ixgbe_tx_ctxtdesc(tx_ring, vlan_macip_lens, 0, type_tucmd, 0);
}

#define IXGBE_SET_FLAG(_input, _flag, _result) \
Expand Down Expand Up @@ -9190,41 +9148,37 @@ static int ixgbe_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

#endif
netdev->features = NETIF_F_SG |
NETIF_F_IP_CSUM |
NETIF_F_IPV6_CSUM |
NETIF_F_HW_VLAN_CTAG_TX |
NETIF_F_HW_VLAN_CTAG_RX |
NETIF_F_TSO |
NETIF_F_TSO6 |
NETIF_F_RXHASH |
NETIF_F_RXCSUM;

netdev->hw_features = netdev->features | NETIF_F_HW_L2FW_DOFFLOAD;
NETIF_F_RXCSUM |
NETIF_F_HW_CSUM |
NETIF_F_HW_VLAN_CTAG_TX |
NETIF_F_HW_VLAN_CTAG_RX;

switch (adapter->hw.mac.type) {
case ixgbe_mac_82599EB:
case ixgbe_mac_X540:
case ixgbe_mac_X550:
case ixgbe_mac_X550EM_x:
if (hw->mac.type >= ixgbe_mac_82599EB)
netdev->features |= NETIF_F_SCTP_CRC;
netdev->hw_features |= NETIF_F_SCTP_CRC |
NETIF_F_NTUPLE |

/* copy netdev features into list of user selectable features */
netdev->hw_features |= netdev->features;
netdev->hw_features |= NETIF_F_RXALL |
NETIF_F_HW_L2FW_DOFFLOAD;

if (hw->mac.type >= ixgbe_mac_82599EB)
netdev->hw_features |= NETIF_F_NTUPLE |
NETIF_F_HW_TC;
break;
default:
break;
}

netdev->hw_features |= NETIF_F_RXALL;
/* set this bit last since it cannot be part of hw_features */
netdev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;

netdev->vlan_features |= NETIF_F_TSO;
netdev->vlan_features |= NETIF_F_TSO6;
netdev->vlan_features |= NETIF_F_IP_CSUM;
netdev->vlan_features |= NETIF_F_IPV6_CSUM;
netdev->vlan_features |= NETIF_F_SG;
netdev->vlan_features |= NETIF_F_SG |
NETIF_F_TSO |
NETIF_F_TSO6 |
NETIF_F_HW_CSUM |
NETIF_F_SCTP_CRC;

netdev->hw_enc_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
netdev->mpls_features |= NETIF_F_HW_CSUM;
netdev->hw_enc_features |= NETIF_F_HW_CSUM;

netdev->priv_flags |= IFF_UNICAST_FLT;
netdev->priv_flags |= IFF_SUPP_NOFCS;
Expand Down

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