1 /* 2 * Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 */ 9 10 #include <linux/module.h> 11 #include <linux/init.h> 12 #include <linux/kernel.h> 13 #include <linux/skbuff.h> 14 #include <linux/rtnetlink.h> 15 #include <linux/filter.h> 16 #include <net/netlink.h> 17 #include <net/pkt_sched.h> 18 19 #include <linux/tc_act/tc_bpf.h> 20 #include <net/tc_act/tc_bpf.h> 21 22 #define BPF_TAB_MASK 15 23 24 static int tcf_bpf(struct sk_buff *skb, const struct tc_action *a, 25 struct tcf_result *res) 26 { 27 struct tcf_bpf *b = a->priv; 28 int action; 29 int filter_res; 30 31 spin_lock(&b->tcf_lock); 32 b->tcf_tm.lastuse = jiffies; 33 bstats_update(&b->tcf_bstats, skb); 34 action = b->tcf_action; 35 36 filter_res = BPF_PROG_RUN(b->filter, skb); 37 if (filter_res == 0) { 38 /* Return code 0 from the BPF program 39 * is being interpreted as a drop here. 40 */ 41 action = TC_ACT_SHOT; 42 b->tcf_qstats.drops++; 43 } 44 45 spin_unlock(&b->tcf_lock); 46 return action; 47 } 48 49 static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *a, 50 int bind, int ref) 51 { 52 unsigned char *tp = skb_tail_pointer(skb); 53 struct tcf_bpf *b = a->priv; 54 struct tc_act_bpf opt = { 55 .index = b->tcf_index, 56 .refcnt = b->tcf_refcnt - ref, 57 .bindcnt = b->tcf_bindcnt - bind, 58 .action = b->tcf_action, 59 }; 60 struct tcf_t t; 61 struct nlattr *nla; 62 63 if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt)) 64 goto nla_put_failure; 65 66 if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, b->bpf_num_ops)) 67 goto nla_put_failure; 68 69 nla = nla_reserve(skb, TCA_ACT_BPF_OPS, b->bpf_num_ops * 70 sizeof(struct sock_filter)); 71 if (!nla) 72 goto nla_put_failure; 73 74 memcpy(nla_data(nla), b->bpf_ops, nla_len(nla)); 75 76 t.install = jiffies_to_clock_t(jiffies - b->tcf_tm.install); 77 t.lastuse = jiffies_to_clock_t(jiffies - b->tcf_tm.lastuse); 78 t.expires = jiffies_to_clock_t(b->tcf_tm.expires); 79 if (nla_put(skb, TCA_ACT_BPF_TM, sizeof(t), &t)) 80 goto nla_put_failure; 81 return skb->len; 82 83 nla_put_failure: 84 nlmsg_trim(skb, tp); 85 return -1; 86 } 87 88 static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = { 89 [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) }, 90 [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 }, 91 [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY, 92 .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, 93 }; 94 95 static int tcf_bpf_init(struct net *net, struct nlattr *nla, 96 struct nlattr *est, struct tc_action *a, 97 int ovr, int bind) 98 { 99 struct nlattr *tb[TCA_ACT_BPF_MAX + 1]; 100 struct tc_act_bpf *parm; 101 struct tcf_bpf *b; 102 u16 bpf_size, bpf_num_ops; 103 struct sock_filter *bpf_ops; 104 struct sock_fprog_kern tmp; 105 struct bpf_prog *fp; 106 int ret; 107 108 if (!nla) 109 return -EINVAL; 110 111 ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy); 112 if (ret < 0) 113 return ret; 114 115 if (!tb[TCA_ACT_BPF_PARMS] || 116 !tb[TCA_ACT_BPF_OPS_LEN] || !tb[TCA_ACT_BPF_OPS]) 117 return -EINVAL; 118 parm = nla_data(tb[TCA_ACT_BPF_PARMS]); 119 120 bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]); 121 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) 122 return -EINVAL; 123 124 bpf_size = bpf_num_ops * sizeof(*bpf_ops); 125 if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS])) 126 return -EINVAL; 127 128 bpf_ops = kzalloc(bpf_size, GFP_KERNEL); 129 if (!bpf_ops) 130 return -ENOMEM; 131 132 memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size); 133 134 tmp.len = bpf_num_ops; 135 tmp.filter = bpf_ops; 136 137 ret = bpf_prog_create(&fp, &tmp); 138 if (ret) 139 goto free_bpf_ops; 140 141 if (!tcf_hash_check(parm->index, a, bind)) { 142 ret = tcf_hash_create(parm->index, est, a, sizeof(*b), bind); 143 if (ret) 144 goto destroy_fp; 145 146 ret = ACT_P_CREATED; 147 } else { 148 if (bind) 149 goto destroy_fp; 150 tcf_hash_release(a, bind); 151 if (!ovr) { 152 ret = -EEXIST; 153 goto destroy_fp; 154 } 155 } 156 157 b = to_bpf(a); 158 spin_lock_bh(&b->tcf_lock); 159 b->tcf_action = parm->action; 160 b->bpf_num_ops = bpf_num_ops; 161 b->bpf_ops = bpf_ops; 162 b->filter = fp; 163 spin_unlock_bh(&b->tcf_lock); 164 165 if (ret == ACT_P_CREATED) 166 tcf_hash_insert(a); 167 return ret; 168 169 destroy_fp: 170 bpf_prog_destroy(fp); 171 free_bpf_ops: 172 kfree(bpf_ops); 173 return ret; 174 } 175 176 static void tcf_bpf_cleanup(struct tc_action *a, int bind) 177 { 178 struct tcf_bpf *b = a->priv; 179 180 bpf_prog_destroy(b->filter); 181 } 182 183 static struct tc_action_ops act_bpf_ops = { 184 .kind = "bpf", 185 .type = TCA_ACT_BPF, 186 .owner = THIS_MODULE, 187 .act = tcf_bpf, 188 .dump = tcf_bpf_dump, 189 .cleanup = tcf_bpf_cleanup, 190 .init = tcf_bpf_init, 191 }; 192 193 static int __init bpf_init_module(void) 194 { 195 return tcf_register_action(&act_bpf_ops, BPF_TAB_MASK); 196 } 197 198 static void __exit bpf_cleanup_module(void) 199 { 200 tcf_unregister_action(&act_bpf_ops); 201 } 202 203 module_init(bpf_init_module); 204 module_exit(bpf_cleanup_module); 205 206 MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>"); 207 MODULE_DESCRIPTION("TC BPF based action"); 208 MODULE_LICENSE("GPL v2"); 209