skb->csum_algo carries the indication on which algorithm is needed to
compute checksum on skb in the transmit path, when skb->ip_summed is
equal to CHECKSUM_PARTIAL. If skb carries a SCTP packet and crc32c
hasn't been yet written in L4 header, skb->csum_algo is assigned to
CRC32C_CHECKSUM. In any other case, skb->csum_algo is set to
INTERNET_CHECKSUM.
Suggested-by: Tom Herbert <tom@xxxxxxxxxxxxxxx>
Signed-off-by: Davide Caratti <dcaratti@xxxxxxxxxx>
---
include/linux/skbuff.h | 28 ++++++++++++++++++++--------
net/core/dev.c | 2 +-
net/netfilter/ipvs/ip_vs_proto_sctp.c | 2 +-
net/netfilter/nf_nat_proto_sctp.c | 2 +-
net/sched/act_csum.c | 2 +-
net/sctp/offload.c | 2 +-
net/sctp/output.c | 3 ++-
7 files changed, 27 insertions(+), 14 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index aaf1072..527be47 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -189,12 +189,13 @@
*
* NETIF_F_SCTP_CRC - This feature indicates that a device is capable of
* offloading the SCTP CRC in a packet. To perform this offload the stack
- * will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
- * accordingly. Note the there is no indication in the skbuff that the
- * CHECKSUM_PARTIAL refers to an SCTP checksum, a driver that supports
- * both IP checksum offload and SCTP CRC offload must verify which offload
- * is configured for a packet presumably by inspecting packet headers; in
- * case, skb_crc32c_csum_help is provided to compute CRC on SCTP packets.
+ * will set set csum_start and csum_offset accordingly, set ip_summed to
+ * CHECKSUM_PARTIAL and set csum_algo to CRC32C_CHECKSUM, to provide an
+ * indication in the skbuff that the CHECKSUM_PARTIAL refers to CRC32c.
+ * A driver that supports both IP checksum offload and SCTP CRC32c offload
+ * must verify which offload is configured for a packet by testing the
+ * value of skb->csum_algo; skb_crc32c_csum_help is provided to resolve
+ * CHECKSUM_PARTIAL on skbs where csum_algo is CRC32C_CHECKSUM.
*
* NETIF_F_FCOE_CRC - This feature indicates that a device is capable of
* offloading the FCOE CRC in a packet. To perform this offload the stack
@@ -614,6 +615,7 @@ static inline bool skb_mstamp_after(const struct skb_mstamp *t1,
* @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
+ * @csum_algo: algorithm used to compute checksum
* @dst_pending_confirm: need to confirm neighbour
* @napi_id: id of the NAPI struct this skb came from
* @secmark: security marking
@@ -742,8 +744,10 @@ struct sk_buff {
__u8 csum_valid:1;
__u8 csum_complete_sw:1;
__u8 csum_level:2;
- __u8 __unused:1; /* one bit hole */
-
+ enum {
+ INTERNET_CHECKSUM = 0,
+ CRC32C_CHECKSUM,
+ } csum_algo:1;
__u8 dst_pending_confirm:1;
#ifdef CONFIG_IPV6_NDISC_NODETYPE
__u8 ndisc_nodetype:2;
@@ -3129,6 +3133,14 @@ struct skb_checksum_ops {
extern const struct skb_checksum_ops *crc32c_csum_stub __read_mostly;
+static inline void skb_set_crc32c_ipsummed(struct sk_buff *skb,
+ const u8 ip_summed)
+{
+ skb->csum_algo = ip_summed == CHECKSUM_PARTIAL ? CRC32C_CHECKSUM :
+ INTERNET_CHECKSUM;
+ skb->ip_summed = ip_summed;
+}
+
__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
__wsum csum, const struct skb_checksum_ops *ops);
__wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
diff --git a/net/core/dev.c b/net/core/dev.c
index 91ba01a..c6a4281 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2641,7 +2641,7 @@ int skb_crc32c_csum_help(struct sk_buff *skb)
goto out;
}
*(__le32 *)(skb->data + offset) = crc32c_csum;
- skb->ip_summed = CHECKSUM_NONE;
+ skb_set_crc32c_ipsummed(skb, CHECKSUM_NONE);
out:
return ret;
}
diff --git a/net/netfilter/ipvs/ip_vs_proto_sctp.c b/net/netfilter/ipvs/ip_vs_proto_sctp.c
index 56f8e4b..8800bf7 100644
--- a/net/netfilter/ipvs/ip_vs_proto_sctp.c
+++ b/net/netfilter/ipvs/ip_vs_proto_sctp.c
@@ -81,7 +81,7 @@ static void sctp_nat_csum(struct sk_buff *skb, sctp_sctphdr_t *sctph,
unsigned int sctphoff)
{
sctph->checksum = sctp_compute_cksum(skb, sctphoff);
- skb->ip_summed = CHECKSUM_UNNECESSARY;
+ skb_set_crc32c_ipsummed(skb, CHECKSUM_UNNECESSARY);
}
static int
diff --git a/net/netfilter/nf_nat_proto_sctp.c b/net/netfilter/nf_nat_proto_sctp.c
index 804e8a0..82a7c4c 100644
--- a/net/netfilter/nf_nat_proto_sctp.c
+++ b/net/netfilter/nf_nat_proto_sctp.c
@@ -60,7 +60,7 @@ sctp_manip_pkt(struct sk_buff *skb,
if (skb->ip_summed != CHECKSUM_PARTIAL) {
hdr->checksum = sctp_compute_cksum(skb, hdroff);
- skb->ip_summed = CHECKSUM_NONE;
+ skb_set_crc32c_ipsummed(skb, CHECKSUM_NONE);
}
return true;
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
index 6c319a4..6e7e862 100644
--- a/net/sched/act_csum.c
+++ b/net/sched/act_csum.c
@@ -349,7 +349,7 @@ static int tcf_csum_sctp(struct sk_buff *skb, unsigned int ihl,
sctph->checksum = sctp_compute_cksum(skb,
skb_network_offset(skb) + ihl);
- skb->ip_summed = CHECKSUM_NONE;
+ skb_set_crc32c_ipsummed(skb, CHECKSUM_NONE);
return 1;
}
diff --git a/net/sctp/offload.c b/net/sctp/offload.c
index 378f462..4b98339 100644
--- a/net/sctp/offload.c
+++ b/net/sctp/offload.c
@@ -34,7 +34,7 @@
static __le32 sctp_gso_make_checksum(struct sk_buff *skb)
{
- skb->ip_summed = CHECKSUM_NONE;
+ skb_set_crc32c_ipsummed(skb, CHECKSUM_NONE);
return sctp_compute_cksum(skb, skb_transport_offset(skb));
}
diff --git a/net/sctp/output.c b/net/sctp/output.c
index 1224421..386cbd8 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -524,10 +524,11 @@ static int sctp_packet_pack(struct sctp_packet *packet,
struct sctphdr *sh =
(struct sctphdr *)skb_transport_header(head);
+ skb_set_crc32c_ipsummed(head, CHECKSUM_NONE);
sh->checksum = sctp_compute_cksum(head, 0);
} else {
chksum:
- head->ip_summed = CHECKSUM_PARTIAL;
+ skb_set_crc32c_ipsummed(head, CHECKSUM_PARTIAL);
head->csum_start = skb_transport_header(head) - head->head;
head->csum_offset = offsetof(struct sctphdr, checksum);
}
--
2.7.4
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