netdev - [PATCH v1 net-next 1/5] ipv6: rpl: Remove pskb(_may)?_pull() in ipv6_rpl_srh

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Message-ID: <20230614230107.22301-2-kuniyu@amazon.com>
Date: Wed, 14 Jun 2023 16:01:03 -0700
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
	<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
	<pabeni@...hat.com>, David Ahern <dsahern@...nel.org>
CC: Kuniyuki Iwashima <kuniyu@...zon.com>, Kuniyuki Iwashima
	<kuni1840@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v1 net-next 1/5] ipv6: rpl: Remove pskb(_may)?_pull() in ipv6_rpl_srh_rcv().

As Eric Dumazet pointed out [0], ipv6_rthdr_rcv() pulls these data

  - Segment Routing Header : 8
  - Hdr Ext Len            : skb_transport_header(skb)[1] << 3

needed by ipv6_rpl_srh_rcv().  We can remove pskb_may_pull() and
replace pskb_pull() with skb_pull() in ipv6_rpl_srh_rcv().

Link: https://lore.kernel.org/netdev/CANn89iLboLwLrHXeHJucAqBkEL_S0rJFog68t7wwwXO-aNf5Mg@mail.gmail.com/ [0]
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
 include/net/rpl.h  |  3 ---
 net/ipv6/exthdrs.c | 17 +----------------
 net/ipv6/rpl.c     |  7 -------
 3 files changed, 1 insertion(+), 26 deletions(-)

diff --git a/include/net/rpl.h b/include/net/rpl.h
index 30fe780d1e7c..74734191c458 100644
--- a/include/net/rpl.h
+++ b/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);
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index a543df57801f..65adc11b59aa 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -517,11 +517,7 @@ 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 +539,6 @@ 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 +558,6 @@ 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;
 
diff --git a/net/ipv6/rpl.c b/net/ipv6/rpl.c
index d1876f192225..e186998bfbf7 100644
--- a/net/ipv6/rpl.c
+++ b/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)
-- 
2.30.2