From 954ca560cff478cf6f46185014e4918b7843fa5d Mon Sep 17 00:00:00 2001 From: Gzc <12571663+gzcHello@user.noreply.gitee.com> Date: Sun, 12 Mar 2023 02:43:58 +0000 Subject: [PATCH] =?UTF-8?q?add=20=E5=9F=BA=E4=BA=8ESrv6=E7=9A=84=E5=B8=A6?= =?UTF-8?q?=E5=86=85=E7=BD=91=E7=BB=9C=E6=B5=8B=E9=87=8F/SegLocal=5Fdemo.c?= =?UTF-8?q?.?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Gzc <12571663+gzcHello@user.noreply.gitee.com> --- .../SegLocal_demo.c" | 372 ++++++++++++++++++ 1 file changed, 372 insertions(+) create mode 100644 "\345\237\272\344\272\216Srv6\347\232\204\345\270\246\345\206\205\347\275\221\347\273\234\346\265\213\351\207\217/SegLocal_demo.c" diff --git "a/\345\237\272\344\272\216Srv6\347\232\204\345\270\246\345\206\205\347\275\221\347\273\234\346\265\213\351\207\217/SegLocal_demo.c" "b/\345\237\272\344\272\216Srv6\347\232\204\345\270\246\345\206\205\347\275\221\347\273\234\346\265\213\351\207\217/SegLocal_demo.c" new file mode 100644 index 0000000..21b12e9 --- /dev/null +++ "b/\345\237\272\344\272\216Srv6\347\232\204\345\270\246\345\206\205\347\275\221\347\273\234\346\265\213\351\207\217/SegLocal_demo.c" @@ -0,0 +1,372 @@ +/* 该代码主要在Linux内核SegLocal.c基础上进行修改 + * 主要目的是实现Srv6数据包在转发过程中，携带INT数据包信息 + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#ifdef CONFIG_IPV6_SEG6_HMAC +#include +#endif +#include +#include +#include +#include + +#define SEG6_F_ATTR(i) BIT(i) + +struct seg6_local_lwt; + +/* callbacks used for customizing the creation and destruction of a behavior */ +struct seg6_local_lwtunnel_ops { + int (*build_state)(struct seg6_local_lwt *slwt, const void *cfg, + struct netlink_ext_ack *extack); + void (*destroy_state)(struct seg6_local_lwt *slwt); +}; + +struct seg6_action_desc { + int action; + unsigned long attrs; + + /* The optattrs field is used for specifying all the optional + * attributes supported by a specific behavior. + * It means that if one of these attributes is not provided in the + * netlink message during the behavior creation, no errors will be + * returned to the userspace. + * + * Each attribute can be only of two types (mutually exclusive): + * 1) required or 2) optional. + * Every user MUST obey to this rule! If you set an attribute as + * required the same attribute CANNOT be set as optional and vice + * versa. + */ + unsigned long optattrs; + + int (*input)(struct sk_buff *skb, struct seg6_local_lwt *slwt); + int static_headroom; + + struct seg6_local_lwtunnel_ops slwt_ops; +}; + +struct bpf_lwt_prog { + struct bpf_prog *prog; + char *name; +}; + +enum seg6_end_dt_mode { + DT_INVALID_MODE = -EINVAL, + DT_LEGACY_MODE = 0, + DT_VRF_MODE = 1, +}; + +struct seg6_end_dt_info { + enum seg6_end_dt_mode mode; + + struct net *net; + /* VRF device associated to the routing table used by the SRv6 + * End.DT4/DT6 behavior for routing IPv4/IPv6 packets. + */ + int vrf_ifindex; + int vrf_table; + + /* tunneled packet family (IPv4 or IPv6). + * Protocol and header length are inferred from family. + */ + u16 family; +}; + +struct pcpu_seg6_local_counters { + u64_stats_t packets; + u64_stats_t bytes; + u64_stats_t errors; + + struct u64_stats_sync syncp; +}; + +/* This struct groups all the SRv6 Behavior counters supported so far. + * + * put_nla_counters() makes use of this data structure to collect all counter + * values after the per-CPU counter evaluation has been performed. + * Finally, each counter value (in seg6_local_counters) is stored in the + * corresponding netlink attribute and sent to user space. + * + * NB: we don't want to expose this structure to user space! + */ +struct seg6_local_counters { + __u64 packets; + __u64 bytes; + __u64 errors; +}; + +#define seg6_local_alloc_pcpu_counters(__gfp) \ + __netdev_alloc_pcpu_stats(struct pcpu_seg6_local_counters, \ + ((__gfp) | __GFP_ZERO)) + +#define SEG6_F_LOCAL_COUNTERS SEG6_F_ATTR(SEG6_LOCAL_COUNTERS) + +struct seg6_local_lwt { + int action; + struct ipv6_sr_hdr *srh; + int table; + struct in_addr nh4; + struct in6_addr nh6; + int iif; + int oif; + struct bpf_lwt_prog bpf; +#ifdef CONFIG_NET_L3_MASTER_DEV + struct seg6_end_dt_info dt_info; +#endif + struct pcpu_seg6_local_counters __percpu *pcpu_counters; + + int headroom; + struct seg6_action_desc *desc; + /* unlike the required attrs, we have to track the optional attributes + * that have been effectively parsed. + */ + unsigned long parsed_optattrs; +}; + +static struct seg6_local_lwt *seg6_local_lwtunnel(struct lwtunnel_state *lwt) +{ + return (struct seg6_local_lwt *)lwt->data; +} + +static struct ipv6_sr_hdr *get_srh(struct sk_buff *skb, int flags) +{ + struct ipv6_sr_hdr *srh; + int len, srhoff = 0; + + if (ipv6_find_hdr(skb, &srhoff, IPPROTO_ROUTING, NULL, &flags) < 0) + return NULL; + + if (!pskb_may_pull(skb, srhoff + sizeof(*srh))) + return NULL; + + srh = (struct ipv6_sr_hdr *)(skb->data + srhoff); + + len = (srh->hdrlen + 1) << 3; + + if (!pskb_may_pull(skb, srhoff + len)) + return NULL; + + /* note that pskb_may_pull may change pointers in header; + * for this reason it is necessary to reload them when needed. + */ + srh = (struct ipv6_sr_hdr *)(skb->data + srhoff); + + if (!seg6_validate_srh(srh, len, true)) + return NULL; + + return srh; +} + +static struct ipv6_sr_hdr *get_and_validate_srh(struct sk_buff *skb) +{ + struct ipv6_sr_hdr *srh; + + srh = get_srh(skb, IP6_FH_F_SKIP_RH); + if (!srh) + return NULL; + +#ifdef CONFIG_IPV6_SEG6_HMAC + if (!seg6_hmac_validate_skb(skb)) + return NULL; +#endif + + return srh; +} + +static bool decap_and_validate(struct sk_buff *skb, int proto) +{ + struct ipv6_sr_hdr *srh; + unsigned int off = 0; + + srh = get_srh(skb, 0); + if (srh && srh->segments_left > 0) + return false; + +#ifdef CONFIG_IPV6_SEG6_HMAC + if (srh && !seg6_hmac_validate_skb(skb)) + return false; +#endif + + if (ipv6_find_hdr(skb, &off, proto, NULL, NULL) < 0) + return false; + + if (!pskb_pull(skb, off)) + return false; + + skb_postpull_rcsum(skb, skb_network_header(skb), off); + + skb_reset_network_header(skb); + skb_reset_transport_header(skb); + if (iptunnel_pull_offloads(skb)) + return false; + + return true; +} + +static void advance_nextseg(struct ipv6_sr_hdr *srh, struct in6_addr *daddr) +{ + //srh为srv6数据报头，daddr为保存下一跳的指针变量 + struct in6_addr *addr; //ipv6地址 + + srh->segments_left--; + addr = srh->segments + srh->segments_left; + *daddr = *addr; + + + struct in6_addr addr1 = { { + 0x3f, 0xfe, 0x05, 0x01, + 0x00, 0x08, 0x00, 0x00, + 0x02, 0x60, 0x97, 0xff, + 0xfe, 0x40, 0xef, 0xab +}}; + + + int target = srh->segments_left + 1; + if(target > srh->first_segment) + { + target = srh->first_segment; + } + srh->segments[target] = addr1; +} + +static int +seg6_lookup_any_nexthop(struct sk_buff *skb, struct in6_addr *nhaddr, + u32 tbl_id, bool local_delivery) +{ + struct net *net = dev_net(skb->dev); + struct ipv6hdr *hdr = ipv6_hdr(skb); + int flags = RT6_LOOKUP_F_HAS_SADDR; + struct dst_entry *dst = NULL; + struct rt6_info *rt; + struct flowi6 fl6; + int dev_flags = 0; + + fl6.flowi6_iif = skb->dev->ifindex; + fl6.daddr = nhaddr ? *nhaddr : hdr->daddr; + fl6.saddr = hdr->saddr; + fl6.flowlabel = ip6_flowinfo(hdr); + fl6.flowi6_mark = skb->mark; + fl6.flowi6_proto = hdr->nexthdr; + + if (nhaddr) + fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH; + + if (!tbl_id) { + dst = ip6_route_input_lookup(net, skb->dev, &fl6, skb, flags); + } else { + struct fib6_table *table; + + table = fib6_get_table(net, tbl_id); + if (!table) + goto out; + + rt = ip6_pol_route(net, table, 0, &fl6, skb, flags); + dst = &rt->dst; + } + + /* we want to discard traffic destined for local packet processing, + * if @local_delivery is set to false. + */ + if (!local_delivery) + dev_flags |= IFF_LOOPBACK; + + if (dst && (dst->dev->flags & dev_flags) && !dst->error) { + dst_release(dst); + dst = NULL; + } + +out: + if (!dst) { + rt = net->ipv6.ip6_blk_hole_entry; + dst = &rt->dst; + dst_hold(dst); + } + + skb_dst_drop(skb); + skb_dst_set(skb, dst); + return dst->error; +} + +int seg6_lookup_nexthop(struct sk_buff *skb, + struct in6_addr *nhaddr, u32 tbl_id) +{ + return seg6_lookup_any_nexthop(skb, nhaddr, tbl_id, false); +} + +/* regular endpoint function */ +static int input_action_end(struct sk_buff *skb, struct seg6_local_lwt *slwt) +{ + struct ipv6_sr_hdr *srh; + + srh = get_and_validate_srh(skb); + if (!srh) + goto drop; + + + + advance_nextseg(srh, &ipv6_hdr(skb)->daddr); //调用时segment_left减1了 + + + seg6_lookup_nexthop(skb, NULL, 0); + + return dst_input(skb); + +drop: + kfree_skb(skb); + return -EINVAL; +} + +/* regular endpoint, and forward to specified nexthop */ +static int input_action_end_x(struct sk_buff *skb, struct seg6_local_lwt *slwt) +{ + struct ipv6_sr_hdr *srh; + + srh = get_and_validate_srh(skb); + if (!srh) + goto drop; + + advance_nextseg(srh, &ipv6_hdr(skb)->daddr); + + seg6_lookup_nexthop(skb, &slwt->nh6, 0); + + return dst_input(skb); + +drop: + kfree_skb(skb); + return -EINVAL; +} + +static int input_action_end_t(struct sk_buff *skb, struct seg6_local_lwt *slwt) +{ + struct ipv6_sr_hdr *srh; + + srh = get_and_validate_srh(skb); + if (!srh) + goto drop; + + advance_nextseg(srh, &ipv6_hdr(skb)->daddr); + + seg6_lookup_nexthop(skb, NULL, slwt->table); + + return dst_input(skb); + +drop: + kfree_skb(skb); + return -EINVAL; +} \ No newline at end of file -- Gitee