diff mbox series

[net-next,v2,1/4] ipv6: ioam: Distinguish input and output for hop-limit

Message ID 20211003184539.23629-2-justin.iurman@uliege.be (mailing list archive)
State Accepted
Commit 52d03786459a7cf4d63a68146409f7a2088aefb2
Delegated to: Netdev Maintainers
Headers show
Series Support for the ip6ip6 encapsulation of IOAM | expand

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netdev/tree_selection success Clearly marked for net-next
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netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/source_inline success Was 0 now: 0
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netdev/module_param success Was 0 now: 0
netdev/build_32bit fail Errors and warnings before: 1 this patch: 5
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 58 lines checked
netdev/build_allmodconfig_warn fail Errors and warnings before: 1 this patch: 5
netdev/header_inline success Link

Commit Message

Justin Iurman Oct. 3, 2021, 6:45 p.m. UTC 
This patch anticipates the support for the IOAM insertion inside in-transit
packets, by making a difference between input and output in order to determine
the right value for its hop-limit (inherited from the IPv6 hop-limit).

Input case: happens before ip6_forward, the IPv6 hop-limit is not decremented
yet -> decrement the IOAM hop-limit to reflect the new hop inside the trace.

Output case: happens after ip6_forward, the IPv6 hop-limit has already been
decremented -> keep the same value for the IOAM hop-limit.

Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
---
 include/net/ioam6.h |  3 ++-
 net/ipv6/exthdrs.c  |  2 +-
 net/ipv6/ioam6.c    | 11 ++++++-----
 3 files changed, 9 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/include/net/ioam6.h b/include/net/ioam6.h
index 3c2993bc48c8..3f45ba37a2c6 100644
--- a/include/net/ioam6.h
+++ b/include/net/ioam6.h
@@ -56,7 +56,8 @@  static inline struct ioam6_pernet_data *ioam6_pernet(struct net *net)
 struct ioam6_namespace *ioam6_namespace(struct net *net, __be16 id);
 void ioam6_fill_trace_data(struct sk_buff *skb,
 			   struct ioam6_namespace *ns,
-			   struct ioam6_trace_hdr *trace);
+			   struct ioam6_trace_hdr *trace,
+			   bool is_input);
 
 int ioam6_init(void);
 void ioam6_exit(void);
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 3a871a09f962..38ece3b7b839 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -979,7 +979,7 @@  static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
 		if (!skb_valid_dst(skb))
 			ip6_route_input(skb);
 
-		ioam6_fill_trace_data(skb, ns, trace);
+		ioam6_fill_trace_data(skb, ns, trace, true);
 		break;
 	default:
 		break;
diff --git a/net/ipv6/ioam6.c b/net/ipv6/ioam6.c
index 5e8961004832..4e5583dbadac 100644
--- a/net/ipv6/ioam6.c
+++ b/net/ipv6/ioam6.c
@@ -631,7 +631,7 @@  static void __ioam6_fill_trace_data(struct sk_buff *skb,
 				    struct ioam6_namespace *ns,
 				    struct ioam6_trace_hdr *trace,
 				    struct ioam6_schema *sc,
-				    u8 sclen)
+				    u8 sclen, bool is_input)
 {
 	struct __kernel_sock_timeval ts;
 	u64 raw64;
@@ -645,7 +645,7 @@  static void __ioam6_fill_trace_data(struct sk_buff *skb,
 	/* hop_lim and node_id */
 	if (trace->type.bit0) {
 		byte = ipv6_hdr(skb)->hop_limit;
-		if (skb->dev)
+		if (is_input)
 			byte--;
 
 		raw32 = dev_net(skb_dst(skb)->dev)->ipv6.sysctl.ioam6_id;
@@ -730,7 +730,7 @@  static void __ioam6_fill_trace_data(struct sk_buff *skb,
 	/* hop_lim and node_id (wide) */
 	if (trace->type.bit8) {
 		byte = ipv6_hdr(skb)->hop_limit;
-		if (skb->dev)
+		if (is_input)
 			byte--;
 
 		raw64 = dev_net(skb_dst(skb)->dev)->ipv6.sysctl.ioam6_id_wide;
@@ -786,7 +786,8 @@  static void __ioam6_fill_trace_data(struct sk_buff *skb,
 /* called with rcu_read_lock() */
 void ioam6_fill_trace_data(struct sk_buff *skb,
 			   struct ioam6_namespace *ns,
-			   struct ioam6_trace_hdr *trace)
+			   struct ioam6_trace_hdr *trace,
+			   bool is_input)
 {
 	struct ioam6_schema *sc;
 	u8 sclen = 0;
@@ -822,7 +823,7 @@  void ioam6_fill_trace_data(struct sk_buff *skb,
 		return;
 	}
 
-	__ioam6_fill_trace_data(skb, ns, trace, sc, sclen);
+	__ioam6_fill_trace_data(skb, ns, trace, sc, sclen, is_input);
 	trace->remlen -= trace->nodelen + sclen;
 }