Add offload capability for performing protocol specific flow dissection
(either by EtherType or IP protocol).
Specifically:
- Add flow_dissect to offload callbacks
- Move flow_dissect_ret enum to flow_dissector.h, cleanup names and add a
couple of values
- Create GOTO_BY_RESULT macro to use in the main flow dissector switch to
simplify handling of functions that return flow_dissect_ret enum
- In __skb_flow_dissect, add default case for switch(proto) as well as
switch(ip_proto) that looks up and calls protocol specific flow
dissection
Signed-off-by: Tom Herbert <t...@quantonium.net>
---
include/linux/netdevice.h | 7 +++
include/net/flow_dissector.h | 9 +++
net/core/dev.c | 14 +++++
net/core/flow_dissector.c | 132 +++++++++++++++++++++++++++++++------------
net/ipv4/route.c | 4 +-
5 files changed, 128 insertions(+), 38 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c5475b37a631..90ccb434e127 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2208,6 +2208,12 @@ struct offload_callbacks {
struct sk_buff **(*gro_receive)(struct sk_buff **head,
struct sk_buff *skb);
int (*gro_complete)(struct sk_buff *skb, int nhoff);
+ enum flow_dissect_ret (*flow_dissect)(const struct sk_buff *skb,
+ struct flow_dissector_key_control *key_control,
+ struct flow_dissector *flow_dissector,
+ void *target_container, void *data,
+ __be16 *p_proto, u8 *p_ip_proto, int *p_nhoff,
+ int *p_hlen, unsigned int flags);
};
struct packet_offload {
@@ -3253,6 +3259,7 @@ struct sk_buff *napi_get_frags(struct napi_struct *napi);
gro_result_t napi_gro_frags(struct napi_struct *napi);
struct packet_offload *gro_find_receive_by_type(__be16 type);
struct packet_offload *gro_find_complete_by_type(__be16 type);
+struct packet_offload *flow_dissect_find_by_type(__be16 type);
static inline void napi_free_frags(struct napi_struct *napi)
{
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index e2663e900b0a..ad75bbfd1c9c 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -19,6 +19,14 @@ struct flow_dissector_key_control {
#define FLOW_DIS_FIRST_FRAG BIT(1)
#define FLOW_DIS_ENCAPSULATION BIT(2)
+enum flow_dissect_ret {
+ FLOW_DISSECT_RET_OUT_GOOD,
+ FLOW_DISSECT_RET_OUT_BAD,
+ FLOW_DISSECT_RET_PROTO_AGAIN,
+ FLOW_DISSECT_RET_IPPROTO_AGAIN,
+ FLOW_DISSECT_RET_CONTINUE,
+};
+
/**
* struct flow_dissector_key_basic:
* @thoff: Transport header offset
@@ -205,6 +213,7 @@ enum flow_dissector_key_id {
#define FLOW_DISSECTOR_F_STOP_AT_L3 BIT(1)
#define FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL BIT(2)
#define FLOW_DISSECTOR_F_STOP_AT_ENCAP BIT(3)
+#define FLOW_DISSECTOR_F_STOP_AT_L4 BIT(4)
struct flow_dissector_key {
enum flow_dissector_key_id key_id;
diff --git a/net/core/dev.c b/net/core/dev.c
index 270b54754821..22ea8daa930c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4860,6 +4860,20 @@ struct packet_offload *gro_find_receive_by_type(__be16
type)
}
EXPORT_SYMBOL(gro_find_receive_by_type);
+struct packet_offload *flow_dissect_find_by_type(__be16 type)
+{
+ struct list_head *offload_head = &offload_base;
+ struct packet_offload *ptype;
+
+ list_for_each_entry_rcu(ptype, offload_head, list) {
+ if (ptype->type != type || !ptype->callbacks.flow_dissect)
+ continue;
+ return ptype;
+ }
+ return NULL;
+}
+EXPORT_SYMBOL(flow_dissect_find_by_type);
+
struct packet_offload *gro_find_complete_by_type(__be16 type)
{
struct list_head *offload_head = &offload_base;
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 12302acdb073..6a2cf240069a 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -9,6 +9,7 @@
#include <net/ipv6.h>
#include <net/gre.h>
#include <net/pptp.h>
+#include <net/protocol.h>
#include <linux/igmp.h>
#include <linux/icmp.h>
#include <linux/sctp.h>
@@ -115,12 +116,6 @@ __be32 __skb_flow_get_ports(const struct sk_buff *skb, int
thoff, u8 ip_proto,
}
EXPORT_SYMBOL(__skb_flow_get_ports);
-enum flow_dissect_ret {
- FLOW_DISSECT_RET_OUT_GOOD,
- FLOW_DISSECT_RET_OUT_BAD,
- FLOW_DISSECT_RET_OUT_PROTO_AGAIN,
-};
-
static enum flow_dissect_ret
__skb_flow_dissect_mpls(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
@@ -322,7 +317,7 @@ __skb_flow_dissect_gre(const struct sk_buff *skb,
if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
return FLOW_DISSECT_RET_OUT_GOOD;
- return FLOW_DISSECT_RET_OUT_PROTO_AGAIN;
+ return FLOW_DISSECT_RET_PROTO_AGAIN;
}
static void
@@ -383,6 +378,27 @@ __skb_flow_dissect_ipv6(const struct sk_buff *skb,
key_ip->ttl = iph->hop_limit;
}
+#define GOTO_BY_RESULT(ret) do { \
+ switch (ret) { \
+ case FLOW_DISSECT_RET_OUT_GOOD: \
+ goto out_good; \
+ case FLOW_DISSECT_RET_PROTO_AGAIN: \
+ goto proto_again; \
+ case FLOW_DISSECT_RET_IPPROTO_AGAIN: \
+ goto ip_proto_again; \
+ case FLOW_DISSECT_RET_OUT_BAD: \
+ default: \
+ goto out_bad; \
+ } \
+} while (0)
+
+#define GOTO_OR_CONT_BY_RESULT(ret) do { \
+ enum flow_dissect_ret __ret = (ret); \
+ \
+ if (__ret != FLOW_DISSECT_RET_CONTINUE) \
+ GOTO_BY_RESULT(__ret); \
+} while (0)
+
/**
* __skb_flow_dissect - extract the flow_keys struct and return it
* @skb: sk_buff to extract the flow from, can be NULL if the rest are
specified
@@ -659,15 +675,10 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
case htons(ETH_P_MPLS_UC):
case htons(ETH_P_MPLS_MC):
mpls:
- switch (__skb_flow_dissect_mpls(skb, flow_dissector,
- target_container, data,
- nhoff, hlen)) {
- case FLOW_DISSECT_RET_OUT_GOOD:
- goto out_good;
- case FLOW_DISSECT_RET_OUT_BAD:
- default:
- goto out_bad;
- }
+ GOTO_BY_RESULT(__skb_flow_dissect_mpls(skb, flow_dissector,
+ target_container, data,
+ nhoff, hlen));
+
case htons(ETH_P_FCOE):
if ((hlen - nhoff) < FCOE_HEADER_LEN)
goto out_bad;
@@ -677,32 +688,44 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
case htons(ETH_P_ARP):
case htons(ETH_P_RARP):
- switch (__skb_flow_dissect_arp(skb, flow_dissector,
- target_container, data,
- nhoff, hlen)) {
- case FLOW_DISSECT_RET_OUT_GOOD:
- goto out_good;
- case FLOW_DISSECT_RET_OUT_BAD:
- default:
- goto out_bad;
+ GOTO_BY_RESULT(__skb_flow_dissect_arp(skb, flow_dissector,
+ target_container, data,
+ nhoff, hlen));
+
+ default: {
+ struct packet_offload *ptype;
+ enum flow_dissect_ret ret;
+
+ rcu_read_lock();
+
+ ptype = flow_dissect_find_by_type(proto);
+
+ if (ptype) {
+ ret = ptype->callbacks.flow_dissect(skb, key_control,
+ flow_dissector,
+ target_container,
+ data, &proto, &ip_proto, &nhoff,
+ &hlen, flags);
+ rcu_read_unlock();
+
+ GOTO_BY_RESULT(ret);
+ } else {
+ rcu_read_unlock();
}
- default:
+
goto out_bad;
}
+ }
ip_proto_again:
switch (ip_proto) {
case IPPROTO_GRE:
- switch (__skb_flow_dissect_gre(skb, key_control, flow_dissector,
- target_container, data,
- &proto, &nhoff, &hlen, flags)) {
- case FLOW_DISSECT_RET_OUT_GOOD:
- goto out_good;
- case FLOW_DISSECT_RET_OUT_BAD:
- goto out_bad;
- case FLOW_DISSECT_RET_OUT_PROTO_AGAIN:
- goto proto_again;
- }
+ GOTO_BY_RESULT(__skb_flow_dissect_gre(skb, key_control,
+ flow_dissector,
+ target_container, data,
+ &proto, &nhoff, &hlen,
+ flags));
+
case NEXTHDR_HOP:
case NEXTHDR_ROUTING:
case NEXTHDR_DEST: {
@@ -768,9 +791,43 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
__skb_flow_dissect_tcp(skb, flow_dissector, target_container,
data, nhoff, hlen);
break;
- default:
+ default: {
+ const struct net_offload *ops = NULL;
+
+ if (flags & FLOW_DISSECTOR_F_STOP_AT_L4)
+ break;
+
+ rcu_read_lock();
+
+ switch (proto) {
+ case htons(ETH_P_IP):
+ ops = rcu_dereference(inet_offloads[ip_proto]);
+ break;
+ case htons(ETH_P_IPV6):
+ ops = rcu_dereference(inet6_offloads[ip_proto]);
+ break;
+ default:
+ break;
+ }
+
+ if (ops && ops->callbacks.flow_dissect) {
+ enum flow_dissect_ret ret;
+
+ ret = ops->callbacks.flow_dissect(skb, key_control,
+ flow_dissector,
+ target_container,
+ data, &proto, &ip_proto, &nhoff,
+ &hlen, flags);
+ rcu_read_unlock();
+
+ GOTO_OR_CONT_BY_RESULT(ret);
+ } else {
+ rcu_read_unlock();
+ }
+
break;
}
+ }
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_PORTS)) {
@@ -935,7 +992,8 @@ static inline u32 ___skb_get_hash(const struct sk_buff *skb,
struct flow_keys *keys, u32 keyval)
{
skb_flow_dissect_flow_keys(skb, keys,
- FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
+ FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL |
+ FLOW_DISSECTOR_F_STOP_AT_L4);
return __flow_hash_from_keys(keys, keyval);
}
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 94d4cd2d5ea4..85f12b8e0b7f 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1811,7 +1811,9 @@ int fib_multipath_hash(const struct fib_info *fi, const
struct flowi4 *fl4,
case 1:
/* skb is currently provided only when forwarding */
if (skb) {
- unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
+ unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP |
+ FLOW_DISSECTOR_F_STOP_AT_L4;
+;
struct flow_keys keys;
/* short-circuit if we already have L4 hash present */
--
2.11.0
