[ovs-dev] [PATCH net-next v2] net: openvswitch: IPv6: Add IPv6 extension header support
Tonghao Zhang
xiangxia.m.yue at gmail.com
Wed May 19 06:24:52 UTC 2021
+ dev at openvswitch.org
On Tue, May 18, 2021 at 12:33 AM Toms Atteka <cpp.code.lv at gmail.com> wrote:
>
> 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 <cpp.code.lv at gmail.com>
> ---
> 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
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