Merge branch 'ipv6-random-cleanup-for-extension-header'

Kuniyuki Iwashima says:

====================
ipv6: Random cleanup for Extension Header.

This series (1) cleans up pskb_may_pull() in some functions, where needed
data are already pulled by their caller, (2) removes redundant multicast
test, and (3) optimises reload timing of the header.
====================

Link: https://lore.kernel.org/r/20230614230107.22301-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/rpl.h

@@ -23,9 +23,6 @@ static inline int rpl_init(void)
 static inline void rpl_exit(void) {}
 #endif
 
-size_t ipv6_rpl_srh_size(unsigned char n, unsigned char cmpri,
-			 unsigned char cmpre);
-
 void ipv6_rpl_srh_decompress(struct ipv6_rpl_sr_hdr *outhdr,
 			     const struct ipv6_rpl_sr_hdr *inhdr,
 			     const struct in6_addr *daddr, unsigned char n);

net/ipv6/exthdrs.c

@@ -126,9 +126,6 @@ static bool ip6_parse_tlv(bool hopbyhop,
 		max_count = -max_count;
 	}
 
-	if (skb_transport_offset(skb) + len > skb_headlen(skb))
-		goto bad;
-
 	off += 2;
 	len -= 2;
 
@@ -402,11 +399,7 @@ static int ipv6_srh_rcv(struct sk_buff *skb)
 
 			skb_postpull_rcsum(skb, skb_network_header(skb),
 					   skb_network_header_len(skb));
-
-			if (!pskb_pull(skb, offset)) {
-				kfree_skb(skb);
-				return -1;
-			}
+			skb_pull(skb, offset);
 			skb_postpull_rcsum(skb, skb_transport_header(skb),
 					   offset);
 
@@ -444,9 +437,9 @@ static int ipv6_srh_rcv(struct sk_buff *skb)
 			kfree_skb(skb);
 			return -1;
 		}
-	}
 
-	hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
+		hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
+	}
 
 	hdr->segments_left--;
 	addr = hdr->segments + hdr->segments_left;
@@ -517,11 +510,7 @@ static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
 
 			skb_postpull_rcsum(skb, skb_network_header(skb),
 					   skb_network_header_len(skb));
-
-			if (!pskb_pull(skb, offset)) {
-				kfree_skb(skb);
-				return -1;
-			}
+			skb_pull(skb, offset);
 			skb_postpull_rcsum(skb, skb_transport_header(skb),
 					   offset);
 
@@ -543,11 +532,6 @@ static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
 		return 1;
 	}
 
-	if (!pskb_may_pull(skb, sizeof(*hdr))) {
-		kfree_skb(skb);
-		return -1;
-	}
-
 	n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
 	r = do_div(n, (16 - hdr->cmpri));
 	/* checks if calculation was without remainder and n fits into
@@ -567,12 +551,6 @@ static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
 		return -1;
 	}
 
-	if (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri,
-						  hdr->cmpre))) {
-		kfree_skb(skb);
-		return -1;
-	}
-
 	hdr->segments_left--;
 	i = n - hdr->segments_left;
 
@@ -586,8 +564,7 @@ static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
 	ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
 	chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
 
-	if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) ||
-	    (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) {
+	if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) {
 		kfree_skb(skb);
 		kfree(buf);
 		return -1;

net/ipv6/rpl.c

@@ -29,13 +29,6 @@ static void *ipv6_rpl_segdata_pos(const struct ipv6_rpl_sr_hdr *hdr, int i)
 	return (void *)&hdr->rpl_segdata[i * IPV6_PFXTAIL_LEN(hdr->cmpri)];
 }
 
-size_t ipv6_rpl_srh_size(unsigned char n, unsigned char cmpri,
-			 unsigned char cmpre)
-{
-	return sizeof(struct ipv6_rpl_sr_hdr) + (n * IPV6_PFXTAIL_LEN(cmpri)) +
-		IPV6_PFXTAIL_LEN(cmpre);
-}
-
 void ipv6_rpl_srh_decompress(struct ipv6_rpl_sr_hdr *outhdr,
 			     const struct ipv6_rpl_sr_hdr *inhdr,
 			     const struct in6_addr *daddr, unsigned char n)