From e4517d8a7f07b18f4f0e68940e2822a1b92b471f Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Fri, 11 Jun 2021 14:05:22 -0500 Subject: [PATCH 1/8] net: qualcomm: rmnet: use ip_is_fragment() In rmnet_map_ipv4_dl_csum_trailer() use ip_is_fragment() to determine whether a socket buffer contains a packet fragment. Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c index cecf72be5102..34bd1a98a101 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -50,8 +50,9 @@ rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb, __be16 addend; ip4h = (struct iphdr *)(skb->data); - if ((ntohs(ip4h->frag_off) & IP_MF) || - ((ntohs(ip4h->frag_off) & IP_OFFSET) > 0)) { + + /* We don't support checksum offload on IPv4 fragments */ + if (ip_is_fragment(ip4h)) { priv->stats.csum_fragmented_pkt++; return -EOPNOTSUPP; } From 75db5b07f8c393c216fd20f7adc9a167fc684c23 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Fri, 11 Jun 2021 14:05:23 -0500 Subject: [PATCH 2/8] net: qualcomm: rmnet: eliminate some ifdefs If IPV6 is not enabled in the kernel configuration, the RMNet checksum code indicates a buffer containing an IPv6 packet is not supported. The same thing happens if a buffer contains something other than an IPv4 or IPv6 packet. We can rearrange things a bit in two functions so that some #ifdef calls can simply be eliminated. Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- .../ethernet/qualcomm/rmnet/rmnet_map_data.c | 56 ++++++++----------- 1 file changed, 24 insertions(+), 32 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c index 34bd1a98a101..b8e504ac7fb1 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -431,21 +431,15 @@ int rmnet_map_checksum_downlink_packet(struct sk_buff *skb, u16 len) return -EINVAL; } - if (skb->protocol == htons(ETH_P_IP)) { + if (skb->protocol == htons(ETH_P_IP)) return rmnet_map_ipv4_dl_csum_trailer(skb, csum_trailer, priv); - } else if (skb->protocol == htons(ETH_P_IPV6)) { -#if IS_ENABLED(CONFIG_IPV6) - return rmnet_map_ipv6_dl_csum_trailer(skb, csum_trailer, priv); -#else - priv->stats.csum_err_invalid_ip_version++; - return -EPROTONOSUPPORT; -#endif - } else { - priv->stats.csum_err_invalid_ip_version++; - return -EPROTONOSUPPORT; - } - return 0; + if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) + return rmnet_map_ipv6_dl_csum_trailer(skb, csum_trailer, priv); + + priv->stats.csum_err_invalid_ip_version++; + + return -EPROTONOSUPPORT; } static void rmnet_map_v4_checksum_uplink_packet(struct sk_buff *skb, @@ -462,28 +456,26 @@ static void rmnet_map_v4_checksum_uplink_packet(struct sk_buff *skb, (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM)))) goto sw_csum; - if (skb->ip_summed == CHECKSUM_PARTIAL) { - iphdr = (char *)ul_header + - sizeof(struct rmnet_map_ul_csum_header); + if (skb->ip_summed != CHECKSUM_PARTIAL) + goto sw_csum; - if (skb->protocol == htons(ETH_P_IP)) { - rmnet_map_ipv4_ul_csum_header(iphdr, ul_header, skb); - priv->stats.csum_hw++; - return; - } else if (skb->protocol == htons(ETH_P_IPV6)) { -#if IS_ENABLED(CONFIG_IPV6) - rmnet_map_ipv6_ul_csum_header(iphdr, ul_header, skb); - priv->stats.csum_hw++; - return; -#else - priv->stats.csum_err_invalid_ip_version++; - goto sw_csum; -#endif - } else { - priv->stats.csum_err_invalid_ip_version++; - } + iphdr = (char *)ul_header + + sizeof(struct rmnet_map_ul_csum_header); + + if (skb->protocol == htons(ETH_P_IP)) { + rmnet_map_ipv4_ul_csum_header(iphdr, ul_header, skb); + priv->stats.csum_hw++; + return; } + if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) { + rmnet_map_ipv6_ul_csum_header(iphdr, ul_header, skb); + priv->stats.csum_hw++; + return; + } + + priv->stats.csum_err_invalid_ip_version++; + sw_csum: memset(ul_header, 0, sizeof(*ul_header)); From 1d257f45ef66796526425afc7d0a9d4dbf57fbb9 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Fri, 11 Jun 2021 14:05:24 -0500 Subject: [PATCH 3/8] net: qualcomm: rmnet: get rid of some local variables The value passed as an argument to rmnet_map_ipv4_ul_csum_header() is always an IPv4 header. Rather than using a local variable, just have the type of the argument reflect the proper type. In rmnet_map_ipv6_ul_csum_header() things are defined a little differently, but make the same basic change there. Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c index b8e504ac7fb1..ca07b87d7ed7 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -195,15 +195,14 @@ static void rmnet_map_complement_ipv4_txporthdr_csum_field(void *iphdr) } static void -rmnet_map_ipv4_ul_csum_header(void *iphdr, +rmnet_map_ipv4_ul_csum_header(struct iphdr *iphdr, struct rmnet_map_ul_csum_header *ul_header, struct sk_buff *skb) { - struct iphdr *ip4h = iphdr; u16 val; val = MAP_CSUM_UL_ENABLED_FLAG; - if (ip4h->protocol == IPPROTO_UDP) + if (iphdr->protocol == IPPROTO_UDP) val |= MAP_CSUM_UL_UDP_FLAG; val |= skb->csum_offset & MAP_CSUM_UL_OFFSET_MASK; @@ -231,15 +230,14 @@ static void rmnet_map_complement_ipv6_txporthdr_csum_field(void *ip6hdr) } static void -rmnet_map_ipv6_ul_csum_header(void *ip6hdr, +rmnet_map_ipv6_ul_csum_header(struct ipv6hdr *ipv6hdr, struct rmnet_map_ul_csum_header *ul_header, struct sk_buff *skb) { - struct ipv6hdr *ip6h = ip6hdr; u16 val; val = MAP_CSUM_UL_ENABLED_FLAG; - if (ip6h->nexthdr == IPPROTO_UDP) + if (ipv6hdr->nexthdr == IPPROTO_UDP) val |= MAP_CSUM_UL_UDP_FLAG; val |= skb->csum_offset & MAP_CSUM_UL_OFFSET_MASK; @@ -248,7 +246,7 @@ rmnet_map_ipv6_ul_csum_header(void *ip6hdr, skb->ip_summed = CHECKSUM_NONE; - rmnet_map_complement_ipv6_txporthdr_csum_field(ip6hdr); + rmnet_map_complement_ipv6_txporthdr_csum_field(ipv6hdr); } #endif From 874a333f7472b2cb57d8528cb26089858ca91005 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Fri, 11 Jun 2021 14:05:25 -0500 Subject: [PATCH 4/8] net: qualcomm: rmnet: simplify rmnet_map_get_csum_field() The checksum fields of the TCP and UDP header structures already have type __sum16. We don't support any other protocol headers, so we can simplify rmnet_map_get_csum_field(), getting rid of the local variable entirely and just returning the appropriate address. Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- .../ethernet/qualcomm/rmnet/rmnet_map_data.c | 20 +++++-------------- 1 file changed, 5 insertions(+), 15 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c index ca07b87d7ed7..79f1d516b5cc 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -19,23 +19,13 @@ static __sum16 *rmnet_map_get_csum_field(unsigned char protocol, const void *txporthdr) { - __sum16 *check = NULL; + if (protocol == IPPROTO_TCP) + return &((struct tcphdr *)txporthdr)->check; - switch (protocol) { - case IPPROTO_TCP: - check = &(((struct tcphdr *)txporthdr)->check); - break; + if (protocol == IPPROTO_UDP) + return &((struct udphdr *)txporthdr)->check; - case IPPROTO_UDP: - check = &(((struct udphdr *)txporthdr)->check); - break; - - default: - check = NULL; - break; - } - - return check; + return NULL; } static int From 16bf3d33c6b042c894747b96580db392b7e6c0c0 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Fri, 11 Jun 2021 14:05:26 -0500 Subject: [PATCH 5/8] net: qualcomm: rmnet: IPv4 header has zero checksum In rmnet_map_ipv4_dl_csum_trailer(), an illegal checksum subtraction is done, subtracting hdr_csum (in host byte order) from csum_value (in network byte order). Despite being illegal, it generally works, because it turns out the value subtracted is (or should be) always 0, which has the same representation in either byte order. Doing illegal operations is not good form though, so fix this by verifying the IP header checksum early in that function. If its checksum is non-zero, the packet will be bad, so just return an error. This will cause the packet to passed to the IP layer where it can be dropped. Thereafter, there is no need subtract the IP header checksum from the checksum value in the trailer because we know it is zero. Add a comment explaining this. This type of packet error is different from other types, so add a new statistics counter to track this condition. Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- .../ethernet/qualcomm/rmnet/rmnet_config.h | 1 + .../ethernet/qualcomm/rmnet/rmnet_map_data.c | 41 ++++++++++++------- .../net/ethernet/qualcomm/rmnet/rmnet_vnd.c | 1 + 3 files changed, 29 insertions(+), 14 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h index 8e64ca98068d..3d3cba56c516 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h @@ -49,6 +49,7 @@ struct rmnet_pcpu_stats { struct rmnet_priv_stats { u64 csum_ok; + u64 csum_ip4_header_bad; u64 csum_valid_unset; u64 csum_validation_failed; u64 csum_err_bad_buffer; diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c index 79f1d516b5cc..40d7e0c615f9 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -33,13 +33,21 @@ rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb, struct rmnet_map_dl_csum_trailer *csum_trailer, struct rmnet_priv *priv) { - __sum16 *csum_field, csum_temp, pseudo_csum, hdr_csum, ip_payload_csum; - u16 csum_value, csum_value_final; - struct iphdr *ip4h; - void *txporthdr; + struct iphdr *ip4h = (struct iphdr *)skb->data; + void *txporthdr = skb->data + ip4h->ihl * 4; + __sum16 *csum_field, csum_temp, pseudo_csum; + __sum16 ip_payload_csum; + u16 csum_value_final; __be16 addend; - ip4h = (struct iphdr *)(skb->data); + /* Computing the checksum over just the IPv4 header--including its + * checksum field--should yield 0. If it doesn't, the IP header + * is bad, so return an error and let the IP layer drop it. + */ + if (ip_fast_csum(ip4h, ip4h->ihl)) { + priv->stats.csum_ip4_header_bad++; + return -EINVAL; + } /* We don't support checksum offload on IPv4 fragments */ if (ip_is_fragment(ip4h)) { @@ -47,25 +55,30 @@ rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb, return -EOPNOTSUPP; } - txporthdr = skb->data + ip4h->ihl * 4; - + /* Checksum offload is only supported for UDP and TCP protocols */ csum_field = rmnet_map_get_csum_field(ip4h->protocol, txporthdr); - if (!csum_field) { priv->stats.csum_err_invalid_transport++; return -EPROTONOSUPPORT; } - /* RFC 768 - Skip IPv4 UDP packets where sender checksum field is 0 */ - if (*csum_field == 0 && ip4h->protocol == IPPROTO_UDP) { + /* RFC 768: UDP checksum is optional for IPv4, and is 0 if unused */ + if (!*csum_field && ip4h->protocol == IPPROTO_UDP) { priv->stats.csum_skipped++; return 0; } - csum_value = ~ntohs(csum_trailer->csum_value); - hdr_csum = ~ip_fast_csum(ip4h, (int)ip4h->ihl); - ip_payload_csum = csum16_sub((__force __sum16)csum_value, - (__force __be16)hdr_csum); + /* The checksum value in the trailer is computed over the entire + * IP packet, including the IP header and payload. To derive the + * transport checksum from this, we first subract the contribution + * of the IP header from the trailer checksum. We then add the + * checksum computed over the pseudo header. + * + * We verified above that the IP header contributes zero to the + * trailer checksum. Therefore the checksum in the trailer is + * just the checksum computed over the IP payload. + */ + ip_payload_csum = (__force __sum16)~ntohs(csum_trailer->csum_value); pseudo_csum = ~csum_tcpudp_magic(ip4h->saddr, ip4h->daddr, ntohs(ip4h->tot_len) - ip4h->ihl * 4, diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c index fe13017e9a41..6556b5381ce8 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c @@ -166,6 +166,7 @@ static const struct net_device_ops rmnet_vnd_ops = { static const char rmnet_gstrings_stats[][ETH_GSTRING_LEN] = { "Checksum ok", + "Bad IPv4 header checksum", "Checksum valid bit not set", "Checksum validation failed", "Checksum error bad buffer", From e5adbbdfa2fb17e3d266011cef816ee492235581 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Fri, 11 Jun 2021 14:05:27 -0500 Subject: [PATCH 6/8] net: qualcomm: rmnet: clarify a bit of code In rmnet_map_ipv6_dl_csum_trailer() there is an especially involved line of code that determines the ones' complement sum of the IPv6 packet header (in host byte order). Simplify that by storing the result of computing just the header checksum in a local variable, then using that in the original assignment. Use the size of the IPv6 header structure as the number of bytes to checksum, rather than computing the offset to the transport header. And use ip_fast_csum() rather than ipa_compute_csum(), knowing that the size of an IPv6 header (40 bytes) is a multiple of 4 bytes greater than 16. Add some comments to match rmnet_map_ipv4_dl_csum_trailer(). Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- .../ethernet/qualcomm/rmnet/rmnet_map_data.c | 26 ++++++++++++------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c index 40d7e0c615f9..4f93355e9a93 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -120,27 +120,33 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb, struct rmnet_map_dl_csum_trailer *csum_trailer, struct rmnet_priv *priv) { - __sum16 *csum_field, ip6_payload_csum, pseudo_csum, csum_temp; + struct ipv6hdr *ip6h = (struct ipv6hdr *)skb->data; + void *txporthdr = skb->data + sizeof(*ip6h); + __sum16 *csum_field, pseudo_csum, csum_temp; u16 csum_value, csum_value_final; __be16 ip6_hdr_csum, addend; - struct ipv6hdr *ip6h; - void *txporthdr; + __sum16 ip6_payload_csum; + __be16 ip_header_csum; u32 length; - ip6h = (struct ipv6hdr *)(skb->data); - - txporthdr = skb->data + sizeof(struct ipv6hdr); + /* Checksum offload is only supported for UDP and TCP protocols; + * the packet cannot include any IPv6 extension headers + */ csum_field = rmnet_map_get_csum_field(ip6h->nexthdr, txporthdr); - if (!csum_field) { priv->stats.csum_err_invalid_transport++; return -EPROTONOSUPPORT; } + /* The checksum value in the trailer is computed over the entire + * IP packet, including the IP header and payload. To derive the + * transport checksum from this, we first subract the contribution + * of the IP header from the trailer checksum. We then add the + * checksum computed over the pseudo header. + */ csum_value = ~ntohs(csum_trailer->csum_value); - ip6_hdr_csum = (__force __be16) - ~ntohs((__force __be16)ip_compute_csum(ip6h, - (int)(txporthdr - (void *)(skb->data)))); + ip_header_csum = (__force __be16)ip_fast_csum(ip6h, sizeof(*ip6h) / 4); + ip6_hdr_csum = (__force __be16)~ntohs(ip_header_csum); ip6_payload_csum = csum16_sub((__force __sum16)csum_value, ip6_hdr_csum); From a2918a169f57f965e4e5949822c2602c90e388ab Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Fri, 11 Jun 2021 14:05:28 -0500 Subject: [PATCH 7/8] net: qualcomm: rmnet: avoid unnecessary byte-swapping Internet checksums are used for IPv4 header checksum, as well as TCP segment and UDP datagram checksums. Such a checksum represents the negated sum of adjacent pairs of bytes, using ones' complement arithmetic. One property of the Internet checkum is byte order independence [1]. Specifically, the sum of byte-swapped pairs is equal to the result of byte swapping the sum of those same pairs when not byte-swapped. So for example if a, b, c, d, y, and z are hexadecimal digits, and PLUS represents ones' complement addition: If: ab PLUS cd = yz Then: ba PLUS dc = zy For this reason, there is no need to swap the order of bytes in the checksum value held in a message header, nor the one in the QMAPv4 trailer, in order to operate on them. In other words, we can determine whether the hardware-computed checksum matches the one in the message header without any byte swaps. (This patch leaves in place all existing type casts.) [1] https://tools.ietf.org/html/rfc1071 Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c index 4f93355e9a93..39f198d7595b 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -78,15 +78,15 @@ rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb, * trailer checksum. Therefore the checksum in the trailer is * just the checksum computed over the IP payload. */ - ip_payload_csum = (__force __sum16)~ntohs(csum_trailer->csum_value); + ip_payload_csum = (__force __sum16)~csum_trailer->csum_value; pseudo_csum = ~csum_tcpudp_magic(ip4h->saddr, ip4h->daddr, ntohs(ip4h->tot_len) - ip4h->ihl * 4, ip4h->protocol, 0); - addend = (__force __be16)ntohs((__force __be16)pseudo_csum); + addend = (__force __be16)pseudo_csum; pseudo_csum = csum16_add(ip_payload_csum, addend); - addend = (__force __be16)ntohs((__force __be16)*csum_field); + addend = (__force __be16)*csum_field; csum_temp = ~csum16_sub(pseudo_csum, addend); csum_value_final = (__force u16)csum_temp; @@ -105,7 +105,7 @@ rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb, } } - if (csum_value_final == ntohs((__force __be16)*csum_field)) { + if (csum_value_final == (__force u16)*csum_field) { priv->stats.csum_ok++; return 0; } else { From 23a5708d4e78a97a8ee0b3bcbf93c81b43504b84 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Fri, 11 Jun 2021 14:05:29 -0500 Subject: [PATCH 8/8] net: qualcomm: rmnet: avoid unnecessary IPv6 byte-swapping In the previous patch IPv4 download checksum offload code was updated to avoid unnecessary byte swapping, based on properties of the Internet checksum algorithm. This patch makes comparable changes to the IPv6 download checksum offload handling. Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- .../ethernet/qualcomm/rmnet/rmnet_map_data.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c index 39f198d7595b..d4d23ab446ef 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -123,10 +123,11 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb, struct ipv6hdr *ip6h = (struct ipv6hdr *)skb->data; void *txporthdr = skb->data + sizeof(*ip6h); __sum16 *csum_field, pseudo_csum, csum_temp; - u16 csum_value, csum_value_final; __be16 ip6_hdr_csum, addend; __sum16 ip6_payload_csum; __be16 ip_header_csum; + u16 csum_value_final; + __be16 csum_value; u32 length; /* Checksum offload is only supported for UDP and TCP protocols; @@ -144,21 +145,21 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb, * of the IP header from the trailer checksum. We then add the * checksum computed over the pseudo header. */ - csum_value = ~ntohs(csum_trailer->csum_value); + csum_value = ~csum_trailer->csum_value; ip_header_csum = (__force __be16)ip_fast_csum(ip6h, sizeof(*ip6h) / 4); - ip6_hdr_csum = (__force __be16)~ntohs(ip_header_csum); + ip6_hdr_csum = (__force __be16)~ip_header_csum; ip6_payload_csum = csum16_sub((__force __sum16)csum_value, ip6_hdr_csum); length = (ip6h->nexthdr == IPPROTO_UDP) ? ntohs(((struct udphdr *)txporthdr)->len) : ntohs(ip6h->payload_len); - pseudo_csum = ~(csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, - length, ip6h->nexthdr, 0)); - addend = (__force __be16)ntohs((__force __be16)pseudo_csum); + pseudo_csum = ~csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, + length, ip6h->nexthdr, 0); + addend = (__force __be16)pseudo_csum; pseudo_csum = csum16_add(ip6_payload_csum, addend); - addend = (__force __be16)ntohs((__force __be16)*csum_field); + addend = (__force __be16)*csum_field; csum_temp = ~csum16_sub(pseudo_csum, addend); csum_value_final = (__force u16)csum_temp; @@ -179,7 +180,7 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb, } } - if (csum_value_final == ntohs((__force __be16)*csum_field)) { + if (csum_value_final == (__force u16)*csum_field) { priv->stats.csum_ok++; return 0; } else {