[Cerowrt-devel] was filled with hope for killing the last traps, now have brick

[Dave Taht <dave.taht@gmail.com>]

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Mine and Robert Bradley's latest attempt at killing the last ipv6
instruction traps
with a rollup patch from bugs 419 and 421...

brick the router. It boots, the main green light goes on, then it dies.
Naturally
I left the serial cable at the office...

Of course in the middle of this patch set revision I also updated to 3.7.3
and openwrt head,
so have a few more variables than usual than just us to cope with.

I would not mind eyeballs on this to see if there is an obvious flaw,
otherwise I will progressively bisect from what was known to work
forward as fast as I can. (besides, the hope is to  submit this upstream)

net_hdr_word is defined in the 902-unaligned_access_hacks patch in openwrt
head...

now off to find a small, sharp, pointy object...

-- 
Dave Täht

Fixing bufferbloat with cerowrt:
http://www.teklibre.com/cerowrt/subscribe.html

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From fb1fe9159a8854ceece937f43b0cef56abf499ce Mon Sep 17 00:00:00 2001
From: Dave Taht <dave.taht@bufferbloat.net>
Date: Sat, 19 Jan 2013 22:31:40 -0800
Subject: [PATCH] full ipv6 unaligne patchset

---
 include/linux/ipv6.h                   |    2 +-
 include/net/addrconf.h                 |    2 +-
 include/net/inet_ecn.h                 |    4 ++--
 include/net/ipv6.h                     |   10 +++++++---
 include/net/ndisc.h                    |    8 +++++---
 include/uapi/linux/in.h                |    2 +-
 include/uapi/linux/xfrm.h              |    2 +-
 net/core/secure_seq.c                  |    9 ++++++---
 net/ipv6/ip6_fib.c                     |    2 +-
 net/netfilter/nf_conntrack_proto_tcp.c |    2 +-
 net/netfilter/xt_LOG.c                 |    4 ++--
 net/xfrm/xfrm_input.c                  |    4 ++--
 12 files changed, 30 insertions(+), 21 deletions(-)

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 74a90be..8fa93bc 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -74,7 +74,7 @@ static inline struct ipv6hdr *ipipv6_hdr(const struct sk_buff *skb)
 
 static inline __u8 ipv6_tclass(const struct ipv6hdr *iph)
 {
-	return (ntohl(*(__be32 *)iph) >> 20) & 0xff;
+	return (ntohl(net_hdr_word(iph)) >> 20) & 0xff;
 }
 
 /* 
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 9e63e76..1fe6a38 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -39,7 +39,7 @@ struct prefix_info {
 	__be32			reserved2;
 
 	struct in6_addr		prefix;
-};
+} __attribute__((packed, aligned(2)));
 
 
 #include <linux/netdevice.h>
diff --git a/include/net/inet_ecn.h b/include/net/inet_ecn.h
index aab7375..5da1768 100644
--- a/include/net/inet_ecn.h
+++ b/include/net/inet_ecn.h
@@ -115,13 +115,13 @@ static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
 {
 	if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
 		return 0;
-	*(__be32*)iph |= htonl(INET_ECN_CE << 20);
+	net_hdr_word(iph) |= htonl(INET_ECN_CE << 20);
 	return 1;
 }
 
 static inline void IP6_ECN_clear(struct ipv6hdr *iph)
 {
-	*(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
+	net_hdr_word(iph) &= ~htonl(INET_ECN_MASK << 20);
 }
 
 static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 979bf6c..e2b6975 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -376,6 +376,8 @@ static inline bool __ipv6_prefix_equal(const __be32 *a1, const __be32 *a2,
 				       unsigned int prefixlen)
 {
 	unsigned int pdw, pbi;
+	/* Used for last <32-bit fraction of prefix */
+	u32 pbia1, pbia2;
 
 	/* check complete u32 in prefix */
 	pdw = prefixlen >> 5;
@@ -384,7 +386,9 @@ static inline bool __ipv6_prefix_equal(const __be32 *a1, const __be32 *a2,
 
 	/* check incomplete u32 in prefix */
 	pbi = prefixlen & 0x1f;
-	if (pbi && ((a1[pdw] ^ a2[pdw]) & htonl((0xffffffff) << (32 - pbi))))
+	pbia1 = net_hdr_word(&a1[pdw]);
+	pbia2 = net_hdr_word(&a2[pdw]);
+	if (pbi && ((pbia1 ^ pbia2) & htonl((0xffffffff) << (32 - pbi))))
 		return false;
 
 	return true;
@@ -500,13 +504,13 @@ static inline void ipv6_addr_set_v4mapped(const __be32 addr,
  */
 static inline int __ipv6_addr_diff(const void *token1, const void *token2, int addrlen)
 {
-	const __be32 *a1 = token1, *a2 = token2;
+	const struct in6_addr *a1 = token1, *a2 = token2;
 	int i;
 
 	addrlen >>= 2;
 
 	for (i = 0; i < addrlen; i++) {
-		__be32 xb = a1[i] ^ a2[i];
+		__be32 xb = a1->s6_addr32[i] ^ a2->s6_addr32[i];
 		if (xb)
 			return i * 32 + 31 - __fls(ntohl(xb));
 	}
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index e61a388..b79fef2 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -76,7 +76,7 @@ struct ra_msg {
         struct icmp6hdr		icmph;
 	__be32			reachable_time;
 	__be32			retrans_timer;
-};
+} __attribute__((packed, aligned(2)));
 
 struct rd_msg {
 	struct icmp6hdr icmph;
@@ -163,8 +163,10 @@ static inline struct neighbour *__ipv6_neigh_lookup(struct neigh_table *tbl, str
 	     n = rcu_dereference_bh(n->next)) {
 		u32 *n32 = (u32 *) n->primary_key;
 		if (n->dev == dev &&
-		    ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
-		     (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0) {
+		    ((n32[0] ^ net_hdr_word(&p32[0])) |
+		     (n32[1] ^ net_hdr_word(&p32[1])) |
+		     (n32[2] ^ net_hdr_word(&p32[2])) |
+		     (n32[3] ^ net_hdr_word(&p32[3]))) == 0) {
 			if (!atomic_inc_not_zero(&n->refcnt))
 				n = NULL;
 			break;
diff --git a/include/uapi/linux/in.h b/include/uapi/linux/in.h
index 9edb441..860de7a 100644
--- a/include/uapi/linux/in.h
+++ b/include/uapi/linux/in.h
@@ -55,7 +55,7 @@ enum {
 /* Internet address. */
 struct in_addr {
 	__be32	s_addr;
-};
+} __attribute__((packed, aligned(2)));
 
 #define IP_TOS		1
 #define IP_TTL		2
diff --git a/include/uapi/linux/xfrm.h b/include/uapi/linux/xfrm.h
index 28e493b..74a9d71 100644
--- a/include/uapi/linux/xfrm.h
+++ b/include/uapi/linux/xfrm.h
@@ -13,7 +13,7 @@
 typedef union {
 	__be32		a4;
 	__be32		a6[4];
-} xfrm_address_t;
+} __attribute__((packed, aligned(2))) xfrm_address_t;
 
 /* Ident of a specific xfrm_state. It is used on input to lookup
  * the state by (spi,daddr,ah/esp) or to store information about
diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c
index e61a8bb..4005c6a 100644
--- a/net/core/secure_seq.c
+++ b/net/core/secure_seq.c
@@ -43,10 +43,11 @@ __u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr,
 	u32 secret[MD5_MESSAGE_BYTES / 4];
 	u32 hash[MD5_DIGEST_WORDS];
 	u32 i;
+	const struct in6_addr *daddr6 = (struct in6_addr *) daddr;
 
 	memcpy(hash, saddr, 16);
 	for (i = 0; i < 4; i++)
-		secret[i] = net_secret[i] + (__force u32)daddr[i];
+		secret[i] = net_secret[i] + (__force u32)daddr6->s6_addr32[i];
 	secret[4] = net_secret[4] +
 		(((__force u16)sport << 16) + (__force u16)dport);
 	for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
@@ -64,10 +65,11 @@ u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
 	u32 secret[MD5_MESSAGE_BYTES / 4];
 	u32 hash[MD5_DIGEST_WORDS];
 	u32 i;
+	const struct in6_addr *daddr6 = (struct in6_addr *) daddr;
 
 	memcpy(hash, saddr, 16);
 	for (i = 0; i < 4; i++)
-		secret[i] = net_secret[i] + (__force u32) daddr[i];
+		secret[i] = net_secret[i] + (__force u32) daddr6->s6_addr32[i];
 	secret[4] = net_secret[4] + (__force u32)dport;
 	for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
 		secret[i] = net_secret[i];
@@ -165,10 +167,11 @@ u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
 	u32 hash[MD5_DIGEST_WORDS];
 	u64 seq;
 	u32 i;
+	const struct in6_addr *daddr6 = (struct in6_addr *) daddr;
 
 	memcpy(hash, saddr, 16);
 	for (i = 0; i < 4; i++)
-		secret[i] = net_secret[i] + daddr[i];
+		secret[i] = net_secret[i] +  daddr6->s6_addr32[i];
 	secret[4] = net_secret[4] +
 		(((__force u16)sport << 16) + (__force u16)dport);
 	for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 24995a9..946abd7 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -144,7 +144,7 @@ static __inline__ __be32 addr_bit_set(const void *token, int fn_bit)
 	 * See include/asm-generic/bitops/le.h.
 	 */
 	return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
-	       addr[fn_bit >> 5];
+	       net_hdr_word(addr[fn_bit >> 5]);
 }
 
 static __inline__ struct fib6_node * node_alloc(void)
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index 61f9285..7893df6 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -449,7 +449,7 @@ static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
 
 	/* Fast path for timestamp-only option */
 	if (length == TCPOLEN_TSTAMP_ALIGNED
-	    && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24)
+	    && net_hdr_word(ptr) == htonl((TCPOPT_NOP << 24)
 				       | (TCPOPT_NOP << 16)
 				       | (TCPOPT_TIMESTAMP << 8)
 				       | TCPOLEN_TIMESTAMP))
diff --git a/net/netfilter/xt_LOG.c b/net/netfilter/xt_LOG.c
index fa40096..2616ecf 100644
--- a/net/netfilter/xt_LOG.c
+++ b/net/netfilter/xt_LOG.c
@@ -521,9 +521,9 @@ static void dump_ipv6_packet(struct sbuff *m,
 	/* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
 	sb_add(m, "LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
 	       ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
-	       (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
+	       (ntohl(net_hdr_word(ih)) & 0x0ff00000) >> 20,
 	       ih->hop_limit,
-	       (ntohl(*(__be32 *)ih) & 0x000fffff));
+	       (ntohl(net_hdr_word(ih)) & 0x000fffff));
 
 	fragment = 0;
 	ptr = ip6hoff + sizeof(struct ipv6hdr);
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index ab2bb42..57bbd3f 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -77,8 +77,8 @@ int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
 	if (!pskb_may_pull(skb, hlen))
 		return -EINVAL;
 
-	*spi = *(__be32*)(skb_transport_header(skb) + offset);
-	*seq = *(__be32*)(skb_transport_header(skb) + offset_seq);
+	*spi = net_hdr_word(skb_transport_header(skb) + offset);
+	*seq = net_hdr_word(skb_transport_header(skb) + offset_seq);
 	return 0;
 }
 
-- 
1.7.9.5

diff --git a/include/net/secure_seq.h b/include/net/secure_seq.h
index c2e542b..daeeec9 100644
--- a/include/net/secure_seq.h
+++ b/include/net/secure_seq.h
@@ -2,6 +2,7 @@
 #define _NET_SECURE_SEQ
 
 #include <linux/types.h>
+#include <linux/in6.h>
 
 extern __u32 secure_ip_id(__be32 daddr);
 extern __u32 secure_ipv6_id(const __be32 daddr[4]);