1/*
2 * m_bpf.c	BPF based action module
3 *
4 *              This program is free software; you can redistribute it and/or
5 *              modify it under the terms of the GNU General Public License
6 *              as published by the Free Software Foundation; either version
7 *              2 of the License, or (at your option) any later version.
8 *
9 * Authors:     Jiri Pirko <jiri@resnulli.us>
10 *              Daniel Borkmann <daniel@iogearbox.net>
11 */
12
13#include <stdio.h>
14#include <stdlib.h>
15
16#include <linux/bpf.h>
17#include <linux/tc_act/tc_bpf.h>
18
19#include "utils.h"
20#include "tc_util.h"
21#include "tc_bpf.h"
22
23static const enum bpf_prog_type bpf_type = BPF_PROG_TYPE_SCHED_ACT;
24
25static const int nla_tbl[BPF_NLA_MAX] = {
26	[BPF_NLA_OPS_LEN]	= TCA_ACT_BPF_OPS_LEN,
27	[BPF_NLA_OPS]		= TCA_ACT_BPF_OPS,
28	[BPF_NLA_FD]		= TCA_ACT_BPF_FD,
29	[BPF_NLA_NAME]		= TCA_ACT_BPF_NAME,
30};
31
32static void explain(void)
33{
34	fprintf(stderr, "Usage: ... bpf ... [ index INDEX ]\n");
35	fprintf(stderr, "\n");
36	fprintf(stderr, "BPF use case:\n");
37	fprintf(stderr, " bytecode BPF_BYTECODE\n");
38	fprintf(stderr, " bytecode-file FILE\n");
39	fprintf(stderr, "\n");
40	fprintf(stderr, "eBPF use case:\n");
41	fprintf(stderr, " object-file FILE [ section ACT_NAME ] [ export UDS_FILE ]");
42	fprintf(stderr, " [ verbose ]\n");
43	fprintf(stderr, " object-pinned FILE\n");
44	fprintf(stderr, "\n");
45	fprintf(stderr, "Where BPF_BYTECODE := \'s,c t f k,c t f k,c t f k,...\'\n");
46	fprintf(stderr, "c,t,f,k and s are decimals; s denotes number of 4-tuples\n");
47	fprintf(stderr, "\n");
48	fprintf(stderr, "Where FILE points to a file containing the BPF_BYTECODE string,\n");
49	fprintf(stderr, "an ELF file containing eBPF map definitions and bytecode, or a\n");
50	fprintf(stderr, "pinned eBPF program.\n");
51	fprintf(stderr, "\n");
52	fprintf(stderr, "Where ACT_NAME refers to the section name containing the\n");
53	fprintf(stderr, "action (default \'%s\').\n", bpf_default_section(bpf_type));
54	fprintf(stderr, "\n");
55	fprintf(stderr, "Where UDS_FILE points to a unix domain socket file in order\n");
56	fprintf(stderr, "to hand off control of all created eBPF maps to an agent.\n");
57	fprintf(stderr, "\n");
58	fprintf(stderr, "Where optionally INDEX points to an existing action, or\n");
59	fprintf(stderr, "explicitly specifies an action index upon creation.\n");
60}
61
62static int bpf_parse_opt(struct action_util *a, int *ptr_argc, char ***ptr_argv,
63			 int tca_id, struct nlmsghdr *n)
64{
65	const char *bpf_obj = NULL, *bpf_uds_name = NULL;
66	struct tc_act_bpf parm;
67	bool seen_run = false;
68	struct rtattr *tail;
69	int argc, ret = 0;
70	char **argv;
71
72	argv = *ptr_argv;
73	argc = *ptr_argc;
74
75	if (matches(*argv, "bpf") != 0)
76		return -1;
77
78	NEXT_ARG();
79
80	tail = NLMSG_TAIL(n);
81	addattr_l(n, MAX_MSG, tca_id, NULL, 0);
82
83	while (argc > 0) {
84		if (matches(*argv, "run") == 0) {
85			NEXT_ARG();
86opt_bpf:
87			seen_run = true;
88			if (bpf_parse_common(&argc, &argv, nla_tbl, bpf_type,
89					     &bpf_obj, &bpf_uds_name, n)) {
90				fprintf(stderr, "Failed to retrieve (e)BPF data!\n");
91				return -1;
92			}
93		} else if (matches(*argv, "help") == 0) {
94			explain();
95			return -1;
96		} else if (matches(*argv, "index") == 0) {
97			break;
98		} else {
99			if (!seen_run)
100				goto opt_bpf;
101			break;
102		}
103
104		NEXT_ARG_FWD();
105	}
106
107	memset(&parm, 0, sizeof(parm));
108	parm.action = TC_ACT_PIPE;
109
110	if (argc) {
111		if (matches(*argv, "reclassify") == 0) {
112			parm.action = TC_ACT_RECLASSIFY;
113			NEXT_ARG_FWD();
114		} else if (matches(*argv, "pipe") == 0) {
115			parm.action = TC_ACT_PIPE;
116			NEXT_ARG_FWD();
117		} else if (matches(*argv, "drop") == 0 ||
118			   matches(*argv, "shot") == 0) {
119			parm.action = TC_ACT_SHOT;
120			NEXT_ARG_FWD();
121		} else if (matches(*argv, "continue") == 0) {
122			parm.action = TC_ACT_UNSPEC;
123			NEXT_ARG_FWD();
124		} else if (matches(*argv, "pass") == 0 ||
125			   matches(*argv, "ok") == 0) {
126			parm.action = TC_ACT_OK;
127			NEXT_ARG_FWD();
128		}
129	}
130
131	if (argc) {
132		if (matches(*argv, "index") == 0) {
133			NEXT_ARG();
134			if (get_u32(&parm.index, *argv, 10)) {
135				fprintf(stderr, "bpf: Illegal \"index\"\n");
136				return -1;
137			}
138
139			NEXT_ARG_FWD();
140		}
141	}
142
143	addattr_l(n, MAX_MSG, TCA_ACT_BPF_PARMS, &parm, sizeof(parm));
144	tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
145
146	if (bpf_uds_name)
147		ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
148
149	*ptr_argc = argc;
150	*ptr_argv = argv;
151
152	return ret;
153}
154
155static int bpf_print_opt(struct action_util *au, FILE *f, struct rtattr *arg)
156{
157	struct rtattr *tb[TCA_ACT_BPF_MAX + 1];
158	struct tc_act_bpf *parm;
159	SPRINT_BUF(action_buf);
160
161	if (arg == NULL)
162		return -1;
163
164	parse_rtattr_nested(tb, TCA_ACT_BPF_MAX, arg);
165
166	if (!tb[TCA_ACT_BPF_PARMS]) {
167		fprintf(f, "[NULL bpf parameters]");
168		return -1;
169	}
170
171	parm = RTA_DATA(tb[TCA_ACT_BPF_PARMS]);
172	fprintf(f, "bpf ");
173
174	if (tb[TCA_ACT_BPF_NAME])
175		fprintf(f, "%s ", rta_getattr_str(tb[TCA_ACT_BPF_NAME]));
176	else if (tb[TCA_ACT_BPF_FD])
177		fprintf(f, "pfd %u ", rta_getattr_u32(tb[TCA_ACT_BPF_FD]));
178
179	if (tb[TCA_ACT_BPF_OPS] && tb[TCA_ACT_BPF_OPS_LEN]) {
180		bpf_print_ops(f, tb[TCA_ACT_BPF_OPS],
181			      rta_getattr_u16(tb[TCA_ACT_BPF_OPS_LEN]));
182		fprintf(f, " ");
183	}
184
185	fprintf(f, "default-action %s\n", action_n2a(parm->action, action_buf,
186		sizeof(action_buf)));
187	fprintf(f, "\tindex %d ref %d bind %d", parm->index, parm->refcnt,
188		parm->bindcnt);
189
190	if (show_stats) {
191		if (tb[TCA_ACT_BPF_TM]) {
192			struct tcf_t *tm = RTA_DATA(tb[TCA_ACT_BPF_TM]);
193			print_tm(f, tm);
194		}
195	}
196
197	fprintf(f, "\n ");
198	return 0;
199}
200
201struct action_util bpf_action_util = {
202	.id		= "bpf",
203	.parse_aopt	= bpf_parse_opt,
204	.print_aopt	= bpf_print_opt,
205};
206