Re: [PATCH net-next v2] net: openvswitch: IPv6: Add IPv6 extension header support
From: Tonghao Zhang <hidden>
Date: 2021-05-19 06:25:45
+ dev@openvswitch.org On Tue, May 18, 2021 at 12:33 AM Toms Atteka [off-list ref] wrote:
quoted hunk ↗ jump to hunk
IPv6 extension headers carry optional internet layer information and are placed between the fixed header and the upper-layer protocol header. This change adds a new OpenFlow field OFPXMT_OFB_IPV6_EXTHDR and packets can be filtered using ipv6_ext flag. Tested-at: https://github.com/TomCodeLV/ovs/actions/runs/504185214 Signed-off-by: Toms Atteka <redacted> --- include/uapi/linux/openvswitch.h | 1 + net/openvswitch/flow.c | 141 +++++++++++++++++++++++++++++++ net/openvswitch/flow.h | 14 +++ net/openvswitch/flow_netlink.c | 5 +- 4 files changed, 160 insertions(+), 1 deletion(-)diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h index 8d16744edc31..a19812b6631a 100644 --- a/include/uapi/linux/openvswitch.h +++ b/include/uapi/linux/openvswitch.h@@ -420,6 +420,7 @@ struct ovs_key_ipv6 { __u8 ipv6_tclass; __u8 ipv6_hlimit; __u8 ipv6_frag; /* One of OVS_FRAG_TYPE_*. */ + __u16 ipv6_exthdr; }; struct ovs_key_tcp {diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c index e586424d8b04..cfc5f395f82c 100644 --- a/net/openvswitch/flow.c +++ b/net/openvswitch/flow.c@@ -239,6 +239,145 @@ static bool icmphdr_ok(struct sk_buff *skb) sizeof(struct icmphdr)); } +/** + * get_ipv6_ext_hdrs() - Parses packet and sets IPv6 extension header flags. + * + * @skb: Buffer where extension header data starts in packet. + * @nh: IPv6 header. + * @ext_hdrs: Flags are stored here. + * + * OFPIEH12_UNREP is set if more than one of a given IPv6 extension header + * is unexpectedly encountered. (Two destination options headers may be + * expected and would not cause this bit to be set.) + * + * OFPIEH12_UNSEQ is set if IPv6 extension headers were not in the order + * preferred (but not required) by RFC 2460: + * + * When more than one extension header is used in the same packet, it is + * recommended that those headers appear in the following order: + * IPv6 header + * Hop-by-Hop Options header + * Destination Options header + * Routing header + * Fragment header + * Authentication header + * Encapsulating Security Payload header + * Destination Options header + * upper-layer header + */ +static void get_ipv6_ext_hdrs(struct sk_buff *skb, struct ipv6hdr *nh, u16 *ext_hdrs) +{ + int next_type = nh->nexthdr; + unsigned int start = skb_network_offset(skb) + sizeof(struct ipv6hdr); + int dest_options_header_count = 0; + + *ext_hdrs = 0; + + while (ipv6_ext_hdr(next_type)) { + struct ipv6_opt_hdr _hdr, *hp; + + switch (next_type) { + case IPPROTO_NONE: + *ext_hdrs |= OFPIEH12_NONEXT; + /* stop parsing */ + return; + + case IPPROTO_ESP: + if (*ext_hdrs & OFPIEH12_ESP) + *ext_hdrs |= OFPIEH12_UNREP; + if ((*ext_hdrs & ~(OFPIEH12_HOP | + OFPIEH12_DEST | + OFPIEH12_ROUTER | + IPPROTO_FRAGMENT | + OFPIEH12_AUTH | + OFPIEH12_UNREP)) || + dest_options_header_count >= 2) + *ext_hdrs |= OFPIEH12_UNSEQ; + *ext_hdrs |= OFPIEH12_ESP; + break; + + case IPPROTO_AH: + if (*ext_hdrs & OFPIEH12_AUTH) + *ext_hdrs |= OFPIEH12_UNREP; + if ((*ext_hdrs & ~(OFPIEH12_HOP | + OFPIEH12_DEST | + OFPIEH12_ROUTER | + IPPROTO_FRAGMENT | + OFPIEH12_UNREP)) || + dest_options_header_count >= 2) + *ext_hdrs |= OFPIEH12_UNSEQ; + *ext_hdrs |= OFPIEH12_AUTH; + break; + + case IPPROTO_DSTOPTS: + if (dest_options_header_count == 0) { + if (*ext_hdrs & ~(OFPIEH12_HOP | + OFPIEH12_UNREP)) + *ext_hdrs |= OFPIEH12_UNSEQ; + *ext_hdrs |= OFPIEH12_DEST; + } else if (dest_options_header_count == 1) { + if (*ext_hdrs & ~(OFPIEH12_HOP | + OFPIEH12_DEST | + OFPIEH12_ROUTER | + OFPIEH12_FRAG | + OFPIEH12_AUTH | + OFPIEH12_ESP | + OFPIEH12_UNREP)) + *ext_hdrs |= OFPIEH12_UNSEQ; + } else { + *ext_hdrs |= OFPIEH12_UNREP; + } + dest_options_header_count++; + break; + + case IPPROTO_FRAGMENT: + if (*ext_hdrs & OFPIEH12_FRAG) + *ext_hdrs |= OFPIEH12_UNREP; + if ((*ext_hdrs & ~(OFPIEH12_HOP | + OFPIEH12_DEST | + OFPIEH12_ROUTER | + OFPIEH12_UNREP)) || + dest_options_header_count >= 2) + *ext_hdrs |= OFPIEH12_UNSEQ; + *ext_hdrs |= OFPIEH12_FRAG; + break; + + case IPPROTO_ROUTING: + if (*ext_hdrs & OFPIEH12_ROUTER) + *ext_hdrs |= OFPIEH12_UNREP; + if ((*ext_hdrs & ~(OFPIEH12_HOP | + OFPIEH12_DEST | + OFPIEH12_UNREP)) || + dest_options_header_count >= 2) + *ext_hdrs |= OFPIEH12_UNSEQ; + *ext_hdrs |= OFPIEH12_ROUTER; + break; + + case IPPROTO_HOPOPTS: + if (*ext_hdrs & OFPIEH12_HOP) + *ext_hdrs |= OFPIEH12_UNREP; + /* OFPIEH12_HOP is set to 1 if a hop-by-hop IPv6 + * extension header is present as the first extension + * header in the pac ket. + */ + if (*ext_hdrs == 0) + *ext_hdrs |= OFPIEH12_HOP; + else + *ext_hdrs |= OFPIEH12_UNSEQ; + break; + + default: + return; + } + + hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr); + if (!hp) + break; + next_type = hp->nexthdr; + start += ipv6_optlen(hp); + } +} + static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key) { unsigned short frag_off;@@ -254,6 +393,8 @@ static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key) nh = ipv6_hdr(skb); + get_ipv6_ext_hdrs(skb, nh, &key->ipv6.exthdrs); + key->ip.proto = NEXTHDR_NONE; key->ip.tos = ipv6_get_dsfield(nh); key->ip.ttl = nh->hop_limit;diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h index 758a8c77f736..e7a8eafae272 100644 --- a/net/openvswitch/flow.h +++ b/net/openvswitch/flow.h@@ -32,6 +32,19 @@ enum sw_flow_mac_proto { #define SW_FLOW_KEY_INVALID 0x80 #define MPLS_LABEL_DEPTH 3 +/* Bit definitions for IPv6 Extension Header pseudo-field. */ +enum ofp12_ipv6exthdr_flags { + OFPIEH12_NONEXT = 1 << 0, /* "No next header" encountered. */ + OFPIEH12_ESP = 1 << 1, /* Encrypted Sec Payload header present. */ + OFPIEH12_AUTH = 1 << 2, /* Authentication header present. */ + OFPIEH12_DEST = 1 << 3, /* 1 or 2 dest headers present. */ + OFPIEH12_FRAG = 1 << 4, /* Fragment header present. */ + OFPIEH12_ROUTER = 1 << 5, /* Router header present. */ + OFPIEH12_HOP = 1 << 6, /* Hop-by-hop header present. */ + OFPIEH12_UNREP = 1 << 7, /* Unexpected repeats encountered. */ + OFPIEH12_UNSEQ = 1 << 8 /* Unexpected sequencing encountered. */ +}; + /* Store options at the end of the array if they are less than the * maximum size. This allows us to get the benefits of variable length * matching for small options.@@ -121,6 +134,7 @@ struct sw_flow_key { struct in6_addr dst; /* IPv6 destination address. */ } addr; __be32 label; /* IPv6 flow label. */ + u16 exthdrs; /* IPv6 extension header flags */ union { struct { struct in6_addr src;diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c index fd1f809e9bc1..681cd9ddda4a 100644 --- a/net/openvswitch/flow_netlink.c +++ b/net/openvswitch/flow_netlink.c@@ -367,7 +367,7 @@ size_t ovs_key_attr_size(void) + nla_total_size(4) /* OVS_KEY_ATTR_VLAN */ + nla_total_size(0) /* OVS_KEY_ATTR_ENCAP */ + nla_total_size(2) /* OVS_KEY_ATTR_ETHERTYPE */ - + nla_total_size(40) /* OVS_KEY_ATTR_IPV6 */ + + nla_total_size(42) /* OVS_KEY_ATTR_IPV6 */ + nla_total_size(2) /* OVS_KEY_ATTR_ICMPV6 */ + nla_total_size(28); /* OVS_KEY_ATTR_ND */ }@@ -1585,6 +1585,8 @@ static int ovs_key_from_nlattrs(struct net *net, struct sw_flow_match *match, ipv6_key->ipv6_hlimit, is_mask); SW_FLOW_KEY_PUT(match, ip.frag, ipv6_key->ipv6_frag, is_mask); + SW_FLOW_KEY_PUT(match, ipv6.exthdrs, + ipv6_key->ipv6_exthdr, is_mask); SW_FLOW_KEY_MEMCPY(match, ipv6.addr.src, ipv6_key->ipv6_src, sizeof(match->key->ipv6.addr.src),@@ -2113,6 +2115,7 @@ static int __ovs_nla_put_key(const struct sw_flow_key *swkey, ipv6_key->ipv6_tclass = output->ip.tos; ipv6_key->ipv6_hlimit = output->ip.ttl; ipv6_key->ipv6_frag = output->ip.frag; + ipv6_key->ipv6_exthdr = output->ipv6.exthdrs; } else if (swkey->eth.type == htons(ETH_P_NSH)) { if (nsh_key_to_nlattr(&output->nsh, is_mask, skb)) goto nla_put_failure;base-commit: 5d869070569a23aa909c6e7e9d010fc438a492ef -- 2.25.1
-- Best regards, Tonghao