diff mbox series

[net-next,v2,1/7] ipv6: Add ipv6_skip_exthdr_no_rthdr

Message ID 20240701195507.256374-2-tom@herbertland.com (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series drivers: Fix drivers doing TX csum offload with EH | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 857 this patch: 857
netdev/build_tools success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 3 maintainers not CCed: edumazet@google.com pabeni@redhat.com dsahern@kernel.org
netdev/build_clang success Errors and warnings before: 875 this patch: 875
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 2821 this patch: 2821
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 77 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-07-03--12-00 (tests: 666)

Commit Message

Tom Herbert July 1, 2024, 7:55 p.m. UTC
ipv6_skip_exthdr_no_rthdr will be called by drivers that support
protocol specific transmit checksum offload with extension headers.
Protocol specific checksum offload doesn't work with routing headers
since the destination address in the IPv6 header is not the one used
in the pseduo checksum for TCP or UDP. This is not a problem with
protocol agnostic checksum offload.

If a routing header is present then ipv6_skip_exthdr_no_rthdr returns
a value less than zero, this is an indication that the driver should
call skb_checksum_help instead of offloading the checksum which  would
be doomed to cause a packet drop at the receiver due to a bad checksum.

Signed-off-by: Tom Herbert <tom@herbertland.com>
---
 include/net/ipv6.h      | 17 +++++++++++++++--
 net/ipv6/exthdrs_core.c | 25 ++++++++++++++++++-------
 2 files changed, 33 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 88a8e554f7a1..6581fabd1e1e 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -1157,8 +1157,21 @@  void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
 			 u8 *proto);
 
-int ipv6_skip_exthdr(const struct sk_buff *, int start, u8 *nexthdrp,
-		     __be16 *frag_offp);
+int __ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp,
+		       __be16 *frag_offp, bool no_rthdr);
+
+static inline int ipv6_skip_exthdr(const struct sk_buff *skb, int start,
+				   u8 *nexthdrp, __be16 *frag_offp)
+{
+	return __ipv6_skip_exthdr(skb, start, nexthdrp, frag_offp, false);
+}
+
+static inline int ipv6_skip_exthdr_no_rthdr(const struct sk_buff *skb,
+					    int start, u8 *nexthdrp,
+					    __be16 *frag_offp)
+{
+	return __ipv6_skip_exthdr(skb, start, nexthdrp, frag_offp, true);
+}
 
 bool ipv6_ext_hdr(u8 nexthdr);
 
diff --git a/net/ipv6/exthdrs_core.c b/net/ipv6/exthdrs_core.c
index 49e31e4ae7b7..25501777ae05 100644
--- a/net/ipv6/exthdrs_core.c
+++ b/net/ipv6/exthdrs_core.c
@@ -69,8 +69,8 @@  EXPORT_SYMBOL(ipv6_ext_hdr);
  * --ANK (980726)
  */
 
-int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp,
-		     __be16 *frag_offp)
+int __ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp,
+		       __be16 *frag_offp, bool no_rthdr)
 {
 	u8 nexthdr = *nexthdrp;
 
@@ -85,7 +85,8 @@  int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp,
 		hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr);
 		if (!hp)
 			return -1;
-		if (nexthdr == NEXTHDR_FRAGMENT) {
+		switch (nexthdr) {
+		case NEXTHDR_FRAGMENT: {
 			__be16 _frag_off, *fp;
 			fp = skb_header_pointer(skb,
 						start+offsetof(struct frag_hdr,
@@ -97,21 +98,31 @@  int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp,
 
 			*frag_offp = *fp;
 			if (ntohs(*frag_offp) & ~0x7)
-				break;
+				goto out;
 			hdrlen = 8;
-		} else if (nexthdr == NEXTHDR_AUTH)
+			break;
+		}
+		case NEXTHDR_AUTH:
 			hdrlen = ipv6_authlen(hp);
-		else
+			break;
+		case NEXTHDR_ROUTING:
+			if (no_rthdr)
+				return -1;
+			fallthrough;
+		default:
 			hdrlen = ipv6_optlen(hp);
+			break;
+		}
 
 		nexthdr = hp->nexthdr;
 		start += hdrlen;
 	}
 
+out:
 	*nexthdrp = nexthdr;
 	return start;
 }
-EXPORT_SYMBOL(ipv6_skip_exthdr);
+EXPORT_SYMBOL(__ipv6_skip_exthdr);
 
 int ipv6_find_tlv(const struct sk_buff *skb, int offset, int type)
 {