| Message ID | 20240821212212.1795357-6-tom@herbertland.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | flow_dissector: Dissect UDP encapsulation protocols | expand |
Hi Tom, kernel test robot noticed the following build warnings: [auto build test WARNING on net-next/main] url: https://github.com/intel-lab-lkp/linux/commits/Tom-Herbert/ipv6-Add-udp6_lib_lookup-to-IPv6-stubs/20240822-052515 base: net-next/main patch link: https://lore.kernel.org/r/20240821212212.1795357-6-tom%40herbertland.com patch subject: [PATCH net-next v3 05/13] flow_dissector: UDP encap infrastructure config: x86_64-buildonly-randconfig-001-20240822 (https://download.01.org/0day-ci/archive/20240822/202408221600.x6NZMg4C-lkp@intel.com/config) compiler: gcc-12 (Debian 12.2.0-14) 12.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240822/202408221600.x6NZMg4C-lkp@intel.com/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 <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202408221600.x6NZMg4C-lkp@intel.com/ All warnings (new ones prefixed by >>): net/core/flow_dissector.c: In function '__skb_flow_dissect_udp': >> net/core/flow_dissector.c:821:22: warning: unused variable 'sk' [-Wunused-variable] 821 | struct sock *sk; | ^~ >> net/core/flow_dissector.c:819:30: warning: unused variable 'udph' [-Wunused-variable] 819 | const struct udphdr *udph; | ^~~~ vim +/sk +821 net/core/flow_dissector.c 809 810 static enum flow_dissect_ret 811 __skb_flow_dissect_udp(const struct sk_buff *skb, const struct net *net, 812 struct flow_dissector *flow_dissector, 813 void *target_container, const void *data, 814 int *p_nhoff, int hlen, __be16 *p_proto, 815 u8 *p_ip_proto, int base_nhoff, unsigned int flags, 816 unsigned int num_hdrs) 817 { 818 enum flow_dissect_ret ret; > 819 const struct udphdr *udph; 820 struct udphdr _udph; > 821 struct sock *sk; 822 __u8 encap_type; 823 int nhoff; 824 825 if (!(flags & FLOW_DISSECTOR_F_PARSE_UDP_ENCAPS)) 826 return FLOW_DISSECT_RET_OUT_GOOD; 827 828 /* Check that the netns for the skb device is the same as the caller's, 829 * and only dissect UDP if we haven't yet encountered any encapsulation. 830 * The goal is to ensure that the socket lookup is being done in the 831 * right netns. Encapsulations may push packets into different name 832 * spaces, so this scheme is restricting UDP dissection to cases where 833 * they are in the same name spaces or at least the original name space. 834 * This should capture the majority of use cases for UDP encaps, and 835 * if we do encounter a UDP encapsulation within a different namespace 836 * then the only effect is we don't attempt UDP dissection 837 */ 838 if (dev_net(skb->dev) != net || num_hdrs > 0) 839 return FLOW_DISSECT_RET_OUT_GOOD; 840 841 switch (*p_proto) { 842 #ifdef CONFIG_INET 843 case htons(ETH_P_IP): { 844 const struct iphdr *iph; 845 struct iphdr _iph; 846 847 iph = __skb_header_pointer(skb, base_nhoff, sizeof(_iph), data, 848 hlen, &_iph); 849 if (!iph) 850 return FLOW_DISSECT_RET_OUT_BAD; 851 852 udph = __skb_header_pointer(skb, *p_nhoff, sizeof(_udph), data, 853 hlen, &_udph); 854 if (!udph) 855 return FLOW_DISSECT_RET_OUT_BAD; 856 857 rcu_read_lock(); 858 /* Look up the UDPv4 socket and get the encap_type */ 859 sk = __udp4_lib_lookup(net, iph->saddr, udph->source, 860 iph->daddr, udph->dest, 861 inet_iif(skb), inet_sdif(skb), 862 net->ipv4.udp_table, NULL); 863 if (!sk || !udp_sk(sk)->encap_type) { 864 rcu_read_unlock(); 865 return FLOW_DISSECT_RET_OUT_GOOD; 866 } 867 868 encap_type = udp_sk(sk)->encap_type; 869 rcu_read_unlock(); 870 871 break; 872 } 873 #if IS_ENABLED(CONFIG_IPV6) 874 case htons(ETH_P_IPV6): { 875 const struct ipv6hdr *iph; 876 struct ipv6hdr _iph; 877 878 if (!likely(ipv6_stub)) 879 return FLOW_DISSECT_RET_OUT_GOOD; 880 881 iph = __skb_header_pointer(skb, base_nhoff, sizeof(_iph), data, 882 hlen, &_iph); 883 if (!iph) 884 return FLOW_DISSECT_RET_OUT_BAD; 885 886 udph = __skb_header_pointer(skb, *p_nhoff, sizeof(_udph), data, 887 hlen, &_udph); 888 if (!udph) 889 return FLOW_DISSECT_RET_OUT_BAD; 890 891 rcu_read_lock(); 892 /* Look up the UDPv6 socket and get the encap_type */ 893 sk = ipv6_stub->udp6_lib_lookup(net, 894 &iph->saddr, udph->source, 895 &iph->daddr, udph->dest, 896 inet_iif(skb), inet_sdif(skb), 897 net->ipv4.udp_table, NULL); 898 899 if (!sk || !udp_sk(sk)->encap_type) { 900 rcu_read_unlock(); 901 return FLOW_DISSECT_RET_OUT_GOOD; 902 } 903 904 encap_type = udp_sk(sk)->encap_type; 905 rcu_read_unlock(); 906 907 break; 908 } 909 #endif /* CONFIG_IPV6 */ 910 #endif /* CONFIG_INET */ 911 default: 912 return FLOW_DISSECT_RET_OUT_GOOD; 913 } 914 915 nhoff = *p_nhoff + sizeof(_udph); 916 ret = FLOW_DISSECT_RET_OUT_GOOD; 917 918 switch (encap_type) { 919 default: 920 break; 921 } 922 923 switch (ret) { 924 case FLOW_DISSECT_RET_PROTO_AGAIN: 925 *p_ip_proto = 0; 926 fallthrough; 927 case FLOW_DISSECT_RET_IPPROTO_AGAIN: 928 *p_nhoff = nhoff; 929 break; 930 default: 931 break; 932 } 933 934 return ret; 935 } 936
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h index ced79dc8e856..8a868a88a6f1 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -384,6 +384,7 @@ enum flow_dissector_key_id { #define FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL BIT(1) #define FLOW_DISSECTOR_F_STOP_AT_ENCAP BIT(2) #define FLOW_DISSECTOR_F_STOP_BEFORE_ENCAP BIT(3) +#define FLOW_DISSECTOR_F_PARSE_UDP_ENCAPS BIT(4) struct flow_dissector_key { enum flow_dissector_key_id key_id; diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 5170676a224c..a5b1b1badc67 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -13,6 +13,7 @@ #include <net/gre.h> #include <net/pptp.h> #include <net/tipc.h> +#include <net/udp.h> #include <linux/igmp.h> #include <linux/icmp.h> #include <linux/sctp.h> @@ -806,6 +807,133 @@ __skb_flow_dissect_batadv(const struct sk_buff *skb, return FLOW_DISSECT_RET_PROTO_AGAIN; } +static enum flow_dissect_ret +__skb_flow_dissect_udp(const struct sk_buff *skb, const struct net *net, + struct flow_dissector *flow_dissector, + void *target_container, const void *data, + int *p_nhoff, int hlen, __be16 *p_proto, + u8 *p_ip_proto, int base_nhoff, unsigned int flags, + unsigned int num_hdrs) +{ + enum flow_dissect_ret ret; + const struct udphdr *udph; + struct udphdr _udph; + struct sock *sk; + __u8 encap_type; + int nhoff; + + if (!(flags & FLOW_DISSECTOR_F_PARSE_UDP_ENCAPS)) + return FLOW_DISSECT_RET_OUT_GOOD; + + /* Check that the netns for the skb device is the same as the caller's, + * and only dissect UDP if we haven't yet encountered any encapsulation. + * The goal is to ensure that the socket lookup is being done in the + * right netns. Encapsulations may push packets into different name + * spaces, so this scheme is restricting UDP dissection to cases where + * they are in the same name spaces or at least the original name space. + * This should capture the majority of use cases for UDP encaps, and + * if we do encounter a UDP encapsulation within a different namespace + * then the only effect is we don't attempt UDP dissection + */ + if (dev_net(skb->dev) != net || num_hdrs > 0) + return FLOW_DISSECT_RET_OUT_GOOD; + + switch (*p_proto) { +#ifdef CONFIG_INET + case htons(ETH_P_IP): { + const struct iphdr *iph; + struct iphdr _iph; + + iph = __skb_header_pointer(skb, base_nhoff, sizeof(_iph), data, + hlen, &_iph); + if (!iph) + return FLOW_DISSECT_RET_OUT_BAD; + + udph = __skb_header_pointer(skb, *p_nhoff, sizeof(_udph), data, + hlen, &_udph); + if (!udph) + return FLOW_DISSECT_RET_OUT_BAD; + + rcu_read_lock(); + /* Look up the UDPv4 socket and get the encap_type */ + sk = __udp4_lib_lookup(net, iph->saddr, udph->source, + iph->daddr, udph->dest, + inet_iif(skb), inet_sdif(skb), + net->ipv4.udp_table, NULL); + if (!sk || !udp_sk(sk)->encap_type) { + rcu_read_unlock(); + return FLOW_DISSECT_RET_OUT_GOOD; + } + + encap_type = udp_sk(sk)->encap_type; + rcu_read_unlock(); + + break; + } +#if IS_ENABLED(CONFIG_IPV6) + case htons(ETH_P_IPV6): { + const struct ipv6hdr *iph; + struct ipv6hdr _iph; + + if (!likely(ipv6_stub)) + return FLOW_DISSECT_RET_OUT_GOOD; + + iph = __skb_header_pointer(skb, base_nhoff, sizeof(_iph), data, + hlen, &_iph); + if (!iph) + return FLOW_DISSECT_RET_OUT_BAD; + + udph = __skb_header_pointer(skb, *p_nhoff, sizeof(_udph), data, + hlen, &_udph); + if (!udph) + return FLOW_DISSECT_RET_OUT_BAD; + + rcu_read_lock(); + /* Look up the UDPv6 socket and get the encap_type */ + sk = ipv6_stub->udp6_lib_lookup(net, + &iph->saddr, udph->source, + &iph->daddr, udph->dest, + inet_iif(skb), inet_sdif(skb), + net->ipv4.udp_table, NULL); + + if (!sk || !udp_sk(sk)->encap_type) { + rcu_read_unlock(); + return FLOW_DISSECT_RET_OUT_GOOD; + } + + encap_type = udp_sk(sk)->encap_type; + rcu_read_unlock(); + + break; + } +#endif /* CONFIG_IPV6 */ +#endif /* CONFIG_INET */ + default: + return FLOW_DISSECT_RET_OUT_GOOD; + } + + nhoff = *p_nhoff + sizeof(_udph); + ret = FLOW_DISSECT_RET_OUT_GOOD; + + switch (encap_type) { + default: + break; + } + + switch (ret) { + case FLOW_DISSECT_RET_PROTO_AGAIN: + *p_ip_proto = 0; + fallthrough; + case FLOW_DISSECT_RET_IPPROTO_AGAIN: + *p_nhoff = nhoff; + break; + default: + break; + } + + return ret; +} + static void __skb_flow_dissect_tcp(const struct sk_buff *skb, struct flow_dissector *flow_dissector, @@ -1046,6 +1174,7 @@ bool __skb_flow_dissect(const struct net *net, int mpls_lse = 0; int num_hdrs = 0; u8 ip_proto = 0; + int base_nhoff; bool ret; if (!data) { @@ -1168,6 +1297,7 @@ bool __skb_flow_dissect(const struct net *net, proto_again: fdret = FLOW_DISSECT_RET_CONTINUE; + base_nhoff = nhoff; switch (proto) { case htons(ETH_P_IP): { @@ -1649,6 +1779,13 @@ bool __skb_flow_dissect(const struct net *net, data, nhoff, hlen); break; + case IPPROTO_UDP: + fdret = __skb_flow_dissect_udp(skb, net, flow_dissector, + target_container, data, &nhoff, + hlen, &proto, &ip_proto, + base_nhoff, flags, num_hdrs); + break; + case IPPROTO_ICMP: case IPPROTO_ICMPV6: __skb_flow_dissect_icmp(skb, flow_dissector, target_container,
Add infrastructure for parsing into UDP encapsulations Add function __skb_flow_dissect_udp that is called for IPPROTO_UDP. The flag FLOW_DISSECTOR_F_PARSE_UDP_ENCAPS enables parsing of UDP encapsulations. If the flag is set when parsing a UDP packet then a socket lookup is performed. The offset of the base network header, either an IPv4 or IPv6 header, is tracked and passed to __skb_flow_dissect_udp so that it can perform the socket lookup If a socket is found and it's for a UDP encapsulation (encap_type is set in the UDP socket) then a switch is performed on the encap_type value (cases are UDP_ENCAP_* values) An encapsulated packet in UDP can either be indicated by an EtherType or IP protocol. The processing for dissecting a UDP encap protocol returns a flow dissector return code. If FLOW_DISSECT_RET_PROTO_AGAIN or FLOW_DISSECT_RET_IPPROTO_AGAIN is returned then the corresponding encapsulated protocol is dissected. The nhoff is set to point to the header to process. In the case FLOW_DISSECT_RET_PROTO_AGAIN the EtherType protocol is returned and the IP protocol is set to zero. In the case of FLOW_DISSECT_RET_IPPROTO_AGAIN, the IP protocol is returned and the EtherType protocol is returned unchanged Signed-off-by: Tom Herbert <tom@herbertland.com> --- include/net/flow_dissector.h | 1 + net/core/flow_dissector.c | 137 +++++++++++++++++++++++++++++++++++ 2 files changed, 138 insertions(+)