Thomas Gleixner | 5b497af | 2019-05-29 07:18:09 -0700 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 2 | /* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch> |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 3 | */ |
| 4 | |
Jakub Kicinski | b645941 | 2021-12-28 16:49:13 -0800 | [diff] [blame] | 5 | #include <linux/filter.h> |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 6 | #include <linux/kernel.h> |
| 7 | #include <linux/module.h> |
| 8 | #include <linux/skbuff.h> |
| 9 | #include <linux/types.h> |
| 10 | #include <linux/bpf.h> |
| 11 | #include <net/lwtunnel.h> |
Peter Oskolkov | ca78801 | 2019-02-13 11:53:37 -0800 | [diff] [blame] | 12 | #include <net/gre.h> |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 13 | #include <net/ip6_route.h> |
David Ahern | 3616d08 | 2019-03-22 06:06:09 -0700 | [diff] [blame] | 14 | #include <net/ipv6_stubs.h> |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 15 | |
| 16 | struct bpf_lwt_prog { |
| 17 | struct bpf_prog *prog; |
| 18 | char *name; |
| 19 | }; |
| 20 | |
| 21 | struct bpf_lwt { |
| 22 | struct bpf_lwt_prog in; |
| 23 | struct bpf_lwt_prog out; |
| 24 | struct bpf_lwt_prog xmit; |
| 25 | int family; |
| 26 | }; |
| 27 | |
| 28 | #define MAX_PROG_NAME 256 |
| 29 | |
| 30 | static inline struct bpf_lwt *bpf_lwt_lwtunnel(struct lwtunnel_state *lwt) |
| 31 | { |
| 32 | return (struct bpf_lwt *)lwt->data; |
| 33 | } |
| 34 | |
| 35 | #define NO_REDIRECT false |
| 36 | #define CAN_REDIRECT true |
| 37 | |
| 38 | static int run_lwt_bpf(struct sk_buff *skb, struct bpf_lwt_prog *lwt, |
| 39 | struct dst_entry *dst, bool can_redirect) |
| 40 | { |
| 41 | int ret; |
| 42 | |
Cong Wang | e336688 | 2020-12-04 23:59:46 -0800 | [diff] [blame] | 43 | /* Migration disable and BH disable are needed to protect per-cpu |
Dongdong Wang | d9054a1 | 2020-12-04 23:59:45 -0800 | [diff] [blame] | 44 | * redirect_info between BPF prog and skb_do_redirect(). |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 45 | */ |
Cong Wang | e336688 | 2020-12-04 23:59:46 -0800 | [diff] [blame] | 46 | migrate_disable(); |
Dongdong Wang | d9054a1 | 2020-12-04 23:59:45 -0800 | [diff] [blame] | 47 | local_bh_disable(); |
Daniel Borkmann | 6aaae2b | 2017-09-25 02:25:50 +0200 | [diff] [blame] | 48 | bpf_compute_data_pointers(skb); |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 49 | ret = bpf_prog_run_save_cb(lwt->prog, skb); |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 50 | |
| 51 | switch (ret) { |
| 52 | case BPF_OK: |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 53 | case BPF_LWT_REROUTE: |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 54 | break; |
| 55 | |
| 56 | case BPF_REDIRECT: |
| 57 | if (unlikely(!can_redirect)) { |
| 58 | pr_warn_once("Illegal redirect return code in prog %s\n", |
| 59 | lwt->name ? : "<unknown>"); |
| 60 | ret = BPF_OK; |
| 61 | } else { |
Willem de Bruijn | e7c87bd | 2019-01-15 20:19:22 -0500 | [diff] [blame] | 62 | skb_reset_mac_header(skb); |
Yan Zhai | 29b22ba | 2023-08-17 19:58:11 -0700 | [diff] [blame] | 63 | skb_do_redirect(skb); |
| 64 | ret = BPF_REDIRECT; |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 65 | } |
| 66 | break; |
| 67 | |
| 68 | case BPF_DROP: |
| 69 | kfree_skb(skb); |
| 70 | ret = -EPERM; |
| 71 | break; |
| 72 | |
| 73 | default: |
| 74 | pr_warn_once("bpf-lwt: Illegal return value %u, expect packet loss\n", ret); |
| 75 | kfree_skb(skb); |
| 76 | ret = -EINVAL; |
| 77 | break; |
| 78 | } |
| 79 | |
Dongdong Wang | d9054a1 | 2020-12-04 23:59:45 -0800 | [diff] [blame] | 80 | local_bh_enable(); |
Cong Wang | e336688 | 2020-12-04 23:59:46 -0800 | [diff] [blame] | 81 | migrate_enable(); |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 82 | |
| 83 | return ret; |
| 84 | } |
| 85 | |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 86 | static int bpf_lwt_input_reroute(struct sk_buff *skb) |
| 87 | { |
| 88 | int err = -EINVAL; |
| 89 | |
| 90 | if (skb->protocol == htons(ETH_P_IP)) { |
Jiri Benc | 9e8acd9 | 2019-10-09 10:31:24 +0200 | [diff] [blame] | 91 | struct net_device *dev = skb_dst(skb)->dev; |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 92 | struct iphdr *iph = ip_hdr(skb); |
| 93 | |
Jiri Benc | 9e8acd9 | 2019-10-09 10:31:24 +0200 | [diff] [blame] | 94 | dev_hold(dev); |
| 95 | skb_dst_drop(skb); |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 96 | err = ip_route_input_noref(skb, iph->daddr, iph->saddr, |
Jiri Benc | 9e8acd9 | 2019-10-09 10:31:24 +0200 | [diff] [blame] | 97 | iph->tos, dev); |
| 98 | dev_put(dev); |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 99 | } else if (skb->protocol == htons(ETH_P_IPV6)) { |
Jiri Benc | 9e8acd9 | 2019-10-09 10:31:24 +0200 | [diff] [blame] | 100 | skb_dst_drop(skb); |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 101 | err = ipv6_stub->ipv6_route_input(skb); |
| 102 | } else { |
| 103 | err = -EAFNOSUPPORT; |
| 104 | } |
| 105 | |
| 106 | if (err) |
| 107 | goto err; |
| 108 | return dst_input(skb); |
| 109 | |
| 110 | err: |
| 111 | kfree_skb(skb); |
| 112 | return err; |
| 113 | } |
| 114 | |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 115 | static int bpf_input(struct sk_buff *skb) |
| 116 | { |
| 117 | struct dst_entry *dst = skb_dst(skb); |
| 118 | struct bpf_lwt *bpf; |
| 119 | int ret; |
| 120 | |
| 121 | bpf = bpf_lwt_lwtunnel(dst->lwtstate); |
| 122 | if (bpf->in.prog) { |
| 123 | ret = run_lwt_bpf(skb, &bpf->in, dst, NO_REDIRECT); |
| 124 | if (ret < 0) |
| 125 | return ret; |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 126 | if (ret == BPF_LWT_REROUTE) |
| 127 | return bpf_lwt_input_reroute(skb); |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 128 | } |
| 129 | |
| 130 | if (unlikely(!dst->lwtstate->orig_input)) { |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 131 | kfree_skb(skb); |
| 132 | return -EINVAL; |
| 133 | } |
| 134 | |
| 135 | return dst->lwtstate->orig_input(skb); |
| 136 | } |
| 137 | |
| 138 | static int bpf_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
| 139 | { |
| 140 | struct dst_entry *dst = skb_dst(skb); |
| 141 | struct bpf_lwt *bpf; |
| 142 | int ret; |
| 143 | |
| 144 | bpf = bpf_lwt_lwtunnel(dst->lwtstate); |
| 145 | if (bpf->out.prog) { |
| 146 | ret = run_lwt_bpf(skb, &bpf->out, dst, NO_REDIRECT); |
| 147 | if (ret < 0) |
| 148 | return ret; |
| 149 | } |
| 150 | |
| 151 | if (unlikely(!dst->lwtstate->orig_output)) { |
| 152 | pr_warn_once("orig_output not set on dst for prog %s\n", |
| 153 | bpf->out.name); |
| 154 | kfree_skb(skb); |
| 155 | return -EINVAL; |
| 156 | } |
| 157 | |
| 158 | return dst->lwtstate->orig_output(net, sk, skb); |
| 159 | } |
| 160 | |
Eyal Birger | b02d196c | 2022-04-20 19:52:19 +0300 | [diff] [blame] | 161 | static int xmit_check_hhlen(struct sk_buff *skb, int hh_len) |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 162 | { |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 163 | if (skb_headroom(skb) < hh_len) { |
| 164 | int nhead = HH_DATA_ALIGN(hh_len - skb_headroom(skb)); |
| 165 | |
| 166 | if (pskb_expand_head(skb, nhead, 0, GFP_ATOMIC)) |
| 167 | return -ENOMEM; |
| 168 | } |
| 169 | |
| 170 | return 0; |
| 171 | } |
| 172 | |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 173 | static int bpf_lwt_xmit_reroute(struct sk_buff *skb) |
| 174 | { |
| 175 | struct net_device *l3mdev = l3mdev_master_dev_rcu(skb_dst(skb)->dev); |
| 176 | int oif = l3mdev ? l3mdev->ifindex : 0; |
| 177 | struct dst_entry *dst = NULL; |
Peter Oskolkov | fb40588 | 2019-02-14 10:39:31 -0800 | [diff] [blame] | 178 | int err = -EAFNOSUPPORT; |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 179 | struct sock *sk; |
| 180 | struct net *net; |
| 181 | bool ipv4; |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 182 | |
| 183 | if (skb->protocol == htons(ETH_P_IP)) |
| 184 | ipv4 = true; |
| 185 | else if (skb->protocol == htons(ETH_P_IPV6)) |
| 186 | ipv4 = false; |
| 187 | else |
Peter Oskolkov | fb40588 | 2019-02-14 10:39:31 -0800 | [diff] [blame] | 188 | goto err; |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 189 | |
| 190 | sk = sk_to_full_sk(skb->sk); |
| 191 | if (sk) { |
| 192 | if (sk->sk_bound_dev_if) |
| 193 | oif = sk->sk_bound_dev_if; |
| 194 | net = sock_net(sk); |
| 195 | } else { |
| 196 | net = dev_net(skb_dst(skb)->dev); |
| 197 | } |
| 198 | |
| 199 | if (ipv4) { |
| 200 | struct iphdr *iph = ip_hdr(skb); |
| 201 | struct flowi4 fl4 = {}; |
| 202 | struct rtable *rt; |
| 203 | |
| 204 | fl4.flowi4_oif = oif; |
| 205 | fl4.flowi4_mark = skb->mark; |
| 206 | fl4.flowi4_uid = sock_net_uid(net, sk); |
| 207 | fl4.flowi4_tos = RT_TOS(iph->tos); |
| 208 | fl4.flowi4_flags = FLOWI_FLAG_ANYSRC; |
| 209 | fl4.flowi4_proto = iph->protocol; |
| 210 | fl4.daddr = iph->daddr; |
| 211 | fl4.saddr = iph->saddr; |
| 212 | |
| 213 | rt = ip_route_output_key(net, &fl4); |
Peter Oskolkov | fb40588 | 2019-02-14 10:39:31 -0800 | [diff] [blame] | 214 | if (IS_ERR(rt)) { |
| 215 | err = PTR_ERR(rt); |
| 216 | goto err; |
| 217 | } |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 218 | dst = &rt->dst; |
| 219 | } else { |
| 220 | struct ipv6hdr *iph6 = ipv6_hdr(skb); |
| 221 | struct flowi6 fl6 = {}; |
| 222 | |
| 223 | fl6.flowi6_oif = oif; |
| 224 | fl6.flowi6_mark = skb->mark; |
| 225 | fl6.flowi6_uid = sock_net_uid(net, sk); |
| 226 | fl6.flowlabel = ip6_flowinfo(iph6); |
| 227 | fl6.flowi6_proto = iph6->nexthdr; |
| 228 | fl6.daddr = iph6->daddr; |
| 229 | fl6.saddr = iph6->saddr; |
| 230 | |
Sabrina Dubroca | 6c8991f | 2019-12-04 15:35:53 +0100 | [diff] [blame] | 231 | dst = ipv6_stub->ipv6_dst_lookup_flow(net, skb->sk, &fl6, NULL); |
Peter Oskolkov | fb40588 | 2019-02-14 10:39:31 -0800 | [diff] [blame] | 232 | if (IS_ERR(dst)) { |
| 233 | err = PTR_ERR(dst); |
| 234 | goto err; |
| 235 | } |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 236 | } |
| 237 | if (unlikely(dst->error)) { |
Peter Oskolkov | fb40588 | 2019-02-14 10:39:31 -0800 | [diff] [blame] | 238 | err = dst->error; |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 239 | dst_release(dst); |
Peter Oskolkov | fb40588 | 2019-02-14 10:39:31 -0800 | [diff] [blame] | 240 | goto err; |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 241 | } |
| 242 | |
| 243 | /* Although skb header was reserved in bpf_lwt_push_ip_encap(), it |
| 244 | * was done for the previous dst, so we are doing it here again, in |
| 245 | * case the new dst needs much more space. The call below is a noop |
| 246 | * if there is enough header space in skb. |
| 247 | */ |
| 248 | err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); |
| 249 | if (unlikely(err)) |
Peter Oskolkov | fb40588 | 2019-02-14 10:39:31 -0800 | [diff] [blame] | 250 | goto err; |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 251 | |
| 252 | skb_dst_drop(skb); |
| 253 | skb_dst_set(skb, dst); |
| 254 | |
| 255 | err = dst_output(dev_net(skb_dst(skb)->dev), skb->sk, skb); |
| 256 | if (unlikely(err)) |
Yan Zhai | 29b22ba | 2023-08-17 19:58:11 -0700 | [diff] [blame] | 257 | return net_xmit_errno(err); |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 258 | |
| 259 | /* ip[6]_finish_output2 understand LWTUNNEL_XMIT_DONE */ |
| 260 | return LWTUNNEL_XMIT_DONE; |
Peter Oskolkov | fb40588 | 2019-02-14 10:39:31 -0800 | [diff] [blame] | 261 | |
| 262 | err: |
| 263 | kfree_skb(skb); |
| 264 | return err; |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 265 | } |
| 266 | |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 267 | static int bpf_xmit(struct sk_buff *skb) |
| 268 | { |
| 269 | struct dst_entry *dst = skb_dst(skb); |
| 270 | struct bpf_lwt *bpf; |
| 271 | |
| 272 | bpf = bpf_lwt_lwtunnel(dst->lwtstate); |
| 273 | if (bpf->xmit.prog) { |
Eyal Birger | b02d196c | 2022-04-20 19:52:19 +0300 | [diff] [blame] | 274 | int hh_len = dst->dev->hard_header_len; |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 275 | __be16 proto = skb->protocol; |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 276 | int ret; |
| 277 | |
| 278 | ret = run_lwt_bpf(skb, &bpf->xmit, dst, CAN_REDIRECT); |
| 279 | switch (ret) { |
| 280 | case BPF_OK: |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 281 | /* If the header changed, e.g. via bpf_lwt_push_encap, |
| 282 | * BPF_LWT_REROUTE below should have been used if the |
| 283 | * protocol was also changed. |
| 284 | */ |
| 285 | if (skb->protocol != proto) { |
| 286 | kfree_skb(skb); |
| 287 | return -EINVAL; |
| 288 | } |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 289 | /* If the header was expanded, headroom might be too |
| 290 | * small for L2 header to come, expand as needed. |
| 291 | */ |
Eyal Birger | b02d196c | 2022-04-20 19:52:19 +0300 | [diff] [blame] | 292 | ret = xmit_check_hhlen(skb, hh_len); |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 293 | if (unlikely(ret)) |
| 294 | return ret; |
| 295 | |
| 296 | return LWTUNNEL_XMIT_CONTINUE; |
| 297 | case BPF_REDIRECT: |
| 298 | return LWTUNNEL_XMIT_DONE; |
Peter Oskolkov | 3bd0b15 | 2019-02-13 11:53:39 -0800 | [diff] [blame] | 299 | case BPF_LWT_REROUTE: |
| 300 | return bpf_lwt_xmit_reroute(skb); |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 301 | default: |
| 302 | return ret; |
| 303 | } |
| 304 | } |
| 305 | |
| 306 | return LWTUNNEL_XMIT_CONTINUE; |
| 307 | } |
| 308 | |
| 309 | static void bpf_lwt_prog_destroy(struct bpf_lwt_prog *prog) |
| 310 | { |
| 311 | if (prog->prog) |
| 312 | bpf_prog_put(prog->prog); |
| 313 | |
| 314 | kfree(prog->name); |
| 315 | } |
| 316 | |
| 317 | static void bpf_destroy_state(struct lwtunnel_state *lwt) |
| 318 | { |
| 319 | struct bpf_lwt *bpf = bpf_lwt_lwtunnel(lwt); |
| 320 | |
| 321 | bpf_lwt_prog_destroy(&bpf->in); |
| 322 | bpf_lwt_prog_destroy(&bpf->out); |
| 323 | bpf_lwt_prog_destroy(&bpf->xmit); |
| 324 | } |
| 325 | |
| 326 | static const struct nla_policy bpf_prog_policy[LWT_BPF_PROG_MAX + 1] = { |
| 327 | [LWT_BPF_PROG_FD] = { .type = NLA_U32, }, |
| 328 | [LWT_BPF_PROG_NAME] = { .type = NLA_NUL_STRING, |
| 329 | .len = MAX_PROG_NAME }, |
| 330 | }; |
| 331 | |
| 332 | static int bpf_parse_prog(struct nlattr *attr, struct bpf_lwt_prog *prog, |
| 333 | enum bpf_prog_type type) |
| 334 | { |
| 335 | struct nlattr *tb[LWT_BPF_PROG_MAX + 1]; |
| 336 | struct bpf_prog *p; |
| 337 | int ret; |
| 338 | u32 fd; |
| 339 | |
Johannes Berg | 8cb0817 | 2019-04-26 14:07:28 +0200 | [diff] [blame] | 340 | ret = nla_parse_nested_deprecated(tb, LWT_BPF_PROG_MAX, attr, |
| 341 | bpf_prog_policy, NULL); |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 342 | if (ret < 0) |
| 343 | return ret; |
| 344 | |
| 345 | if (!tb[LWT_BPF_PROG_FD] || !tb[LWT_BPF_PROG_NAME]) |
| 346 | return -EINVAL; |
| 347 | |
Taehee Yoo | 71eb525 | 2018-07-29 00:28:31 +0900 | [diff] [blame] | 348 | prog->name = nla_memdup(tb[LWT_BPF_PROG_NAME], GFP_ATOMIC); |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 349 | if (!prog->name) |
| 350 | return -ENOMEM; |
| 351 | |
| 352 | fd = nla_get_u32(tb[LWT_BPF_PROG_FD]); |
| 353 | p = bpf_prog_get_type(fd, type); |
| 354 | if (IS_ERR(p)) |
| 355 | return PTR_ERR(p); |
| 356 | |
| 357 | prog->prog = p; |
| 358 | |
| 359 | return 0; |
| 360 | } |
| 361 | |
| 362 | static const struct nla_policy bpf_nl_policy[LWT_BPF_MAX + 1] = { |
| 363 | [LWT_BPF_IN] = { .type = NLA_NESTED, }, |
| 364 | [LWT_BPF_OUT] = { .type = NLA_NESTED, }, |
| 365 | [LWT_BPF_XMIT] = { .type = NLA_NESTED, }, |
| 366 | [LWT_BPF_XMIT_HEADROOM] = { .type = NLA_U32 }, |
| 367 | }; |
| 368 | |
Alexander Aring | faee676 | 2020-03-27 18:00:21 -0400 | [diff] [blame] | 369 | static int bpf_build_state(struct net *net, struct nlattr *nla, |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 370 | unsigned int family, const void *cfg, |
David Ahern | 9ae2872 | 2017-05-27 16:19:28 -0600 | [diff] [blame] | 371 | struct lwtunnel_state **ts, |
| 372 | struct netlink_ext_ack *extack) |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 373 | { |
| 374 | struct nlattr *tb[LWT_BPF_MAX + 1]; |
| 375 | struct lwtunnel_state *newts; |
| 376 | struct bpf_lwt *bpf; |
| 377 | int ret; |
| 378 | |
| 379 | if (family != AF_INET && family != AF_INET6) |
| 380 | return -EAFNOSUPPORT; |
| 381 | |
Johannes Berg | 8cb0817 | 2019-04-26 14:07:28 +0200 | [diff] [blame] | 382 | ret = nla_parse_nested_deprecated(tb, LWT_BPF_MAX, nla, bpf_nl_policy, |
| 383 | extack); |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 384 | if (ret < 0) |
| 385 | return ret; |
| 386 | |
| 387 | if (!tb[LWT_BPF_IN] && !tb[LWT_BPF_OUT] && !tb[LWT_BPF_XMIT]) |
| 388 | return -EINVAL; |
| 389 | |
| 390 | newts = lwtunnel_state_alloc(sizeof(*bpf)); |
| 391 | if (!newts) |
| 392 | return -ENOMEM; |
| 393 | |
| 394 | newts->type = LWTUNNEL_ENCAP_BPF; |
| 395 | bpf = bpf_lwt_lwtunnel(newts); |
| 396 | |
| 397 | if (tb[LWT_BPF_IN]) { |
| 398 | newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT; |
| 399 | ret = bpf_parse_prog(tb[LWT_BPF_IN], &bpf->in, |
| 400 | BPF_PROG_TYPE_LWT_IN); |
| 401 | if (ret < 0) |
| 402 | goto errout; |
| 403 | } |
| 404 | |
| 405 | if (tb[LWT_BPF_OUT]) { |
| 406 | newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT; |
| 407 | ret = bpf_parse_prog(tb[LWT_BPF_OUT], &bpf->out, |
| 408 | BPF_PROG_TYPE_LWT_OUT); |
| 409 | if (ret < 0) |
| 410 | goto errout; |
| 411 | } |
| 412 | |
| 413 | if (tb[LWT_BPF_XMIT]) { |
| 414 | newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT; |
| 415 | ret = bpf_parse_prog(tb[LWT_BPF_XMIT], &bpf->xmit, |
| 416 | BPF_PROG_TYPE_LWT_XMIT); |
| 417 | if (ret < 0) |
| 418 | goto errout; |
| 419 | } |
| 420 | |
| 421 | if (tb[LWT_BPF_XMIT_HEADROOM]) { |
| 422 | u32 headroom = nla_get_u32(tb[LWT_BPF_XMIT_HEADROOM]); |
| 423 | |
| 424 | if (headroom > LWT_BPF_MAX_HEADROOM) { |
| 425 | ret = -ERANGE; |
| 426 | goto errout; |
| 427 | } |
| 428 | |
| 429 | newts->headroom = headroom; |
| 430 | } |
| 431 | |
| 432 | bpf->family = family; |
| 433 | *ts = newts; |
| 434 | |
| 435 | return 0; |
| 436 | |
| 437 | errout: |
| 438 | bpf_destroy_state(newts); |
| 439 | kfree(newts); |
| 440 | return ret; |
| 441 | } |
| 442 | |
| 443 | static int bpf_fill_lwt_prog(struct sk_buff *skb, int attr, |
| 444 | struct bpf_lwt_prog *prog) |
| 445 | { |
| 446 | struct nlattr *nest; |
| 447 | |
| 448 | if (!prog->prog) |
| 449 | return 0; |
| 450 | |
Michal Kubecek | ae0be8d | 2019-04-26 11:13:06 +0200 | [diff] [blame] | 451 | nest = nla_nest_start_noflag(skb, attr); |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 452 | if (!nest) |
| 453 | return -EMSGSIZE; |
| 454 | |
| 455 | if (prog->name && |
| 456 | nla_put_string(skb, LWT_BPF_PROG_NAME, prog->name)) |
| 457 | return -EMSGSIZE; |
| 458 | |
| 459 | return nla_nest_end(skb, nest); |
| 460 | } |
| 461 | |
| 462 | static int bpf_fill_encap_info(struct sk_buff *skb, struct lwtunnel_state *lwt) |
| 463 | { |
| 464 | struct bpf_lwt *bpf = bpf_lwt_lwtunnel(lwt); |
| 465 | |
| 466 | if (bpf_fill_lwt_prog(skb, LWT_BPF_IN, &bpf->in) < 0 || |
| 467 | bpf_fill_lwt_prog(skb, LWT_BPF_OUT, &bpf->out) < 0 || |
| 468 | bpf_fill_lwt_prog(skb, LWT_BPF_XMIT, &bpf->xmit) < 0) |
| 469 | return -EMSGSIZE; |
| 470 | |
| 471 | return 0; |
| 472 | } |
| 473 | |
| 474 | static int bpf_encap_nlsize(struct lwtunnel_state *lwtstate) |
| 475 | { |
| 476 | int nest_len = nla_total_size(sizeof(struct nlattr)) + |
| 477 | nla_total_size(MAX_PROG_NAME) + /* LWT_BPF_PROG_NAME */ |
| 478 | 0; |
| 479 | |
| 480 | return nest_len + /* LWT_BPF_IN */ |
| 481 | nest_len + /* LWT_BPF_OUT */ |
| 482 | nest_len + /* LWT_BPF_XMIT */ |
| 483 | 0; |
| 484 | } |
| 485 | |
Wei Yongjun | 79471b1 | 2017-01-12 14:39:28 +0000 | [diff] [blame] | 486 | static int bpf_lwt_prog_cmp(struct bpf_lwt_prog *a, struct bpf_lwt_prog *b) |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 487 | { |
| 488 | /* FIXME: |
| 489 | * The LWT state is currently rebuilt for delete requests which |
| 490 | * results in a new bpf_prog instance. Comparing names for now. |
| 491 | */ |
| 492 | if (!a->name && !b->name) |
| 493 | return 0; |
| 494 | |
| 495 | if (!a->name || !b->name) |
| 496 | return 1; |
| 497 | |
| 498 | return strcmp(a->name, b->name); |
| 499 | } |
| 500 | |
| 501 | static int bpf_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b) |
| 502 | { |
| 503 | struct bpf_lwt *a_bpf = bpf_lwt_lwtunnel(a); |
| 504 | struct bpf_lwt *b_bpf = bpf_lwt_lwtunnel(b); |
| 505 | |
| 506 | return bpf_lwt_prog_cmp(&a_bpf->in, &b_bpf->in) || |
| 507 | bpf_lwt_prog_cmp(&a_bpf->out, &b_bpf->out) || |
| 508 | bpf_lwt_prog_cmp(&a_bpf->xmit, &b_bpf->xmit); |
| 509 | } |
| 510 | |
| 511 | static const struct lwtunnel_encap_ops bpf_encap_ops = { |
| 512 | .build_state = bpf_build_state, |
| 513 | .destroy_state = bpf_destroy_state, |
| 514 | .input = bpf_input, |
| 515 | .output = bpf_output, |
| 516 | .xmit = bpf_xmit, |
| 517 | .fill_encap = bpf_fill_encap_info, |
| 518 | .get_encap_size = bpf_encap_nlsize, |
| 519 | .cmp_encap = bpf_encap_cmp, |
Robert Shearman | 88ff733 | 2017-01-24 16:26:47 +0000 | [diff] [blame] | 520 | .owner = THIS_MODULE, |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 521 | }; |
| 522 | |
Peter Oskolkov | ca78801 | 2019-02-13 11:53:37 -0800 | [diff] [blame] | 523 | static int handle_gso_type(struct sk_buff *skb, unsigned int gso_type, |
| 524 | int encap_len) |
| 525 | { |
| 526 | struct skb_shared_info *shinfo = skb_shinfo(skb); |
| 527 | |
| 528 | gso_type |= SKB_GSO_DODGY; |
| 529 | shinfo->gso_type |= gso_type; |
| 530 | skb_decrease_gso_size(shinfo, encap_len); |
| 531 | shinfo->gso_segs = 0; |
| 532 | return 0; |
| 533 | } |
| 534 | |
Peter Oskolkov | 52f2787 | 2019-02-13 11:53:36 -0800 | [diff] [blame] | 535 | static int handle_gso_encap(struct sk_buff *skb, bool ipv4, int encap_len) |
| 536 | { |
Peter Oskolkov | ca78801 | 2019-02-13 11:53:37 -0800 | [diff] [blame] | 537 | int next_hdr_offset; |
| 538 | void *next_hdr; |
| 539 | __u8 protocol; |
| 540 | |
| 541 | /* SCTP and UDP_L4 gso need more nuanced handling than what |
| 542 | * handle_gso_type() does above: skb_decrease_gso_size() is not enough. |
| 543 | * So at the moment only TCP GSO packets are let through. |
| 544 | */ |
| 545 | if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) |
| 546 | return -ENOTSUPP; |
| 547 | |
| 548 | if (ipv4) { |
| 549 | protocol = ip_hdr(skb)->protocol; |
| 550 | next_hdr_offset = sizeof(struct iphdr); |
| 551 | next_hdr = skb_network_header(skb) + next_hdr_offset; |
| 552 | } else { |
| 553 | protocol = ipv6_hdr(skb)->nexthdr; |
| 554 | next_hdr_offset = sizeof(struct ipv6hdr); |
| 555 | next_hdr = skb_network_header(skb) + next_hdr_offset; |
| 556 | } |
| 557 | |
| 558 | switch (protocol) { |
| 559 | case IPPROTO_GRE: |
| 560 | next_hdr_offset += sizeof(struct gre_base_hdr); |
| 561 | if (next_hdr_offset > encap_len) |
| 562 | return -EINVAL; |
| 563 | |
| 564 | if (((struct gre_base_hdr *)next_hdr)->flags & GRE_CSUM) |
| 565 | return handle_gso_type(skb, SKB_GSO_GRE_CSUM, |
| 566 | encap_len); |
| 567 | return handle_gso_type(skb, SKB_GSO_GRE, encap_len); |
| 568 | |
| 569 | case IPPROTO_UDP: |
| 570 | next_hdr_offset += sizeof(struct udphdr); |
| 571 | if (next_hdr_offset > encap_len) |
| 572 | return -EINVAL; |
| 573 | |
| 574 | if (((struct udphdr *)next_hdr)->check) |
| 575 | return handle_gso_type(skb, SKB_GSO_UDP_TUNNEL_CSUM, |
| 576 | encap_len); |
| 577 | return handle_gso_type(skb, SKB_GSO_UDP_TUNNEL, encap_len); |
| 578 | |
| 579 | case IPPROTO_IP: |
| 580 | case IPPROTO_IPV6: |
| 581 | if (ipv4) |
| 582 | return handle_gso_type(skb, SKB_GSO_IPXIP4, encap_len); |
| 583 | else |
| 584 | return handle_gso_type(skb, SKB_GSO_IPXIP6, encap_len); |
| 585 | |
| 586 | default: |
| 587 | return -EPROTONOSUPPORT; |
| 588 | } |
Peter Oskolkov | 52f2787 | 2019-02-13 11:53:36 -0800 | [diff] [blame] | 589 | } |
| 590 | |
| 591 | int bpf_lwt_push_ip_encap(struct sk_buff *skb, void *hdr, u32 len, bool ingress) |
| 592 | { |
| 593 | struct iphdr *iph; |
| 594 | bool ipv4; |
| 595 | int err; |
| 596 | |
| 597 | if (unlikely(len < sizeof(struct iphdr) || len > LWT_BPF_MAX_HEADROOM)) |
| 598 | return -EINVAL; |
| 599 | |
| 600 | /* validate protocol and length */ |
| 601 | iph = (struct iphdr *)hdr; |
| 602 | if (iph->version == 4) { |
| 603 | ipv4 = true; |
| 604 | if (unlikely(len < iph->ihl * 4)) |
| 605 | return -EINVAL; |
| 606 | } else if (iph->version == 6) { |
| 607 | ipv4 = false; |
| 608 | if (unlikely(len < sizeof(struct ipv6hdr))) |
| 609 | return -EINVAL; |
| 610 | } else { |
| 611 | return -EINVAL; |
| 612 | } |
| 613 | |
| 614 | if (ingress) |
| 615 | err = skb_cow_head(skb, len + skb->mac_len); |
| 616 | else |
| 617 | err = skb_cow_head(skb, |
| 618 | len + LL_RESERVED_SPACE(skb_dst(skb)->dev)); |
| 619 | if (unlikely(err)) |
| 620 | return err; |
| 621 | |
| 622 | /* push the encap headers and fix pointers */ |
| 623 | skb_reset_inner_headers(skb); |
Peter Oskolkov | ea0371f | 2019-03-04 16:27:08 -0800 | [diff] [blame] | 624 | skb_reset_inner_mac_header(skb); /* mac header is not yet set */ |
| 625 | skb_set_inner_protocol(skb, skb->protocol); |
Peter Oskolkov | 52f2787 | 2019-02-13 11:53:36 -0800 | [diff] [blame] | 626 | skb->encapsulation = 1; |
| 627 | skb_push(skb, len); |
| 628 | if (ingress) |
| 629 | skb_postpush_rcsum(skb, iph, len); |
| 630 | skb_reset_network_header(skb); |
| 631 | memcpy(skb_network_header(skb), hdr, len); |
| 632 | bpf_compute_data_pointers(skb); |
| 633 | skb_clear_hash(skb); |
| 634 | |
| 635 | if (ipv4) { |
| 636 | skb->protocol = htons(ETH_P_IP); |
| 637 | iph = ip_hdr(skb); |
| 638 | |
| 639 | if (!iph->check) |
| 640 | iph->check = ip_fast_csum((unsigned char *)iph, |
| 641 | iph->ihl); |
| 642 | } else { |
| 643 | skb->protocol = htons(ETH_P_IPV6); |
| 644 | } |
| 645 | |
| 646 | if (skb_is_gso(skb)) |
| 647 | return handle_gso_encap(skb, ipv4, len); |
| 648 | |
| 649 | return 0; |
| 650 | } |
| 651 | |
Thomas Graf | 3a0af8f | 2016-11-30 17:10:10 +0100 | [diff] [blame] | 652 | static int __init bpf_lwt_init(void) |
| 653 | { |
| 654 | return lwtunnel_encap_add_ops(&bpf_encap_ops, LWTUNNEL_ENCAP_BPF); |
| 655 | } |
| 656 | |
| 657 | subsys_initcall(bpf_lwt_init) |