Subject: Re: [PATCH net-next 1/4] virtio-net: a helper for probing the pseudo-header checksum

From: kernel test robot <[email-masked]>
Date: Mon, 19 Jun 2023 20:30:45 +0800

Hi Heng,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Heng-Qi/virtio-net-a-helper-for-probing-the-pseudo-header-checksum/20230619-190212
base:   net-next/main
patch link:    https://lore.kernel.org/r/20230619105738.117733-2-hengqi%40linux.alibaba.com
patch subject: [PATCH net-next 1/4] virtio-net: a helper for probing the pseudo-header checksum
config: x86_64-randconfig-r014-20230619 (https://download.01.org/0day-ci/archive/20230619/[email-masked]/config)
compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
reproduce: (https://download.01.org/0day-ci/archive/20230619/[email-masked]/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email-masked]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email-masked]/

All errors (new ones prefixed by >>):

>> drivers/net/virtio_net.c:1648:17: error: call to undeclared function 'csum_ipv6_magic'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
                           uh->check = ~csum_ipv6_magic((const struct in6_addr *)&ip6h->saddr,
                                        ^
   drivers/net/virtio_net.c:1648:17: note: did you mean 'csum_tcpudp_magic'?
   include/asm-generic/checksum.h:52:1: note: 'csum_tcpudp_magic' declared here
   csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
   ^
   drivers/net/virtio_net.c:1657:17: error: call to undeclared function 'csum_ipv6_magic'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
                           th->check = ~csum_ipv6_magic((const struct in6_addr *)&ip6h->saddr,
                                        ^
   2 errors generated.

vim +/csum_ipv6_magic +1648 drivers/net/virtio_net.c

  1572	
  1573	static int virtnet_flow_dissect_udp_tcp(struct virtnet_info *vi, struct sk_buff *skb)
  1574	{
  1575		struct net_device *dev = vi->dev;
  1576		struct flow_keys_basic keys;
  1577		struct udphdr *uh;
  1578		struct tcphdr *th;
  1579		int len, offset;
  1580	
  1581		/* The flow dissector needs this information. */
  1582		skb->dev = dev;
  1583		skb_reset_mac_header(skb);
  1584		skb->protocol = dev_parse_header_protocol(skb);
  1585		/* virtio-net does not need to resolve VLAN. */
  1586		skb_set_network_header(skb, ETH_HLEN);
  1587		if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
  1588						      NULL, 0, 0, 0, 0))
  1589			return -EINVAL;
  1590	
  1591		/* 1. Pseudo-header checksum calculation requires:
  1592		 *    (1) saddr/daddr (2) IP_PROTO (3) length of transport payload
  1593		 * 2. We don't parse SCTP because virtio-net currently doesn't
  1594		 *    support CRC offloading for SCTP.
  1595		 */
  1596		if (keys.basic.n_proto == htons(ETH_P_IP)) {
  1597			struct iphdr *iph;
  1598	
  1599			/* Flow dissector has verified that there is an IP header. */
  1600			iph = ip_hdr(skb);
  1601			if (iph->version != 4 || !pskb_may_pull(skb, iph->ihl * 4))
  1602				return -EINVAL;
  1603	
  1604			skb->transport_header = skb->mac_header + keys.control.thoff;
  1605			offset = skb_transport_offset(skb);
  1606			len = skb->len - offset;
  1607			if (keys.basic.ip_proto == IPPROTO_UDP) {
  1608				if (!pskb_may_pull(skb, offset + sizeof(struct udphdr)))
  1609					return -EINVAL;
  1610	
  1611				uh = udp_hdr(skb);
  1612				skb->csum_offset = offsetof(struct udphdr, check);
  1613				/* Although uh->len is already the 3rd parameter for the calculation
  1614				 * of the pseudo-header checksum, we have already calculated the
  1615				 * length of the transport layer, so use 'len' here directly.
  1616				 */
  1617				uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, len,
  1618						IPPROTO_UDP, 0);
  1619			} else if (keys.basic.ip_proto == IPPROTO_TCP) {
  1620				if (!pskb_may_pull(skb, offset + sizeof(struct tcphdr)))
  1621					return -EINVAL;
  1622	
  1623				th = tcp_hdr(skb);
  1624				skb->csum_offset = offsetof(struct tcphdr, check);
  1625				th->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, len,
  1626						IPPROTO_TCP, 0);
  1627			} /* virtio-net doesn't support checksums for SCTP hw offloading.*/
  1628		} else if (keys.basic.n_proto == htons(ETH_P_IPV6)) {
  1629			struct ipv6hdr *ip6h;
  1630	
  1631			ip6h = ipv6_hdr(skb);
  1632			if (ip6h->version != 6)
  1633				return -EINVAL;
  1634	
  1635			/* We have skipped the possible extension headers for IPv6.
  1636			 * If there is a Routing Header, the tx's check value is calculated by
  1637			 * final_dst, and that value is the rx's daddr.
  1638			 */
  1639			skb->transport_header = skb->mac_header + keys.control.thoff;
  1640			offset = skb_transport_offset(skb);
  1641			len = skb->len - offset;
  1642			if (keys.basic.ip_proto == IPPROTO_UDP) {
  1643				if (!pskb_may_pull(skb, offset + sizeof(struct udphdr)))
  1644					return -EINVAL;
  1645	
  1646				uh = udp_hdr(skb);
  1647				skb->csum_offset = offsetof(struct udphdr, check);
> 1648				uh->check = ~csum_ipv6_magic((const struct in6_addr *)&ip6h->saddr,
  1649						(const struct in6_addr *)&ip6h->daddr,
  1650						len, IPPROTO_UDP, 0);
  1651			} else if (keys.basic.ip_proto == IPPROTO_TCP) {
  1652				if (!pskb_may_pull(skb, offset + sizeof(struct tcphdr)))
  1653					return -EINVAL;
  1654	
  1655				th = tcp_hdr(skb);
  1656				skb->csum_offset = offsetof(struct tcphdr, check);
  1657				th->check = ~csum_ipv6_magic((const struct in6_addr *)&ip6h->saddr,
  1658						(const struct in6_addr *)&ip6h->daddr,
  1659						len, IPPROTO_TCP, 0);
  1660			}
  1661		}
  1662	
  1663		skb->csum_start = skb->transport_header;
  1664	
  1665		return 0;
  1666	}
  1667	

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