1/*
2 * m_csum.c	checksum updating action
3 *
4 *		This program is free software; you can distribute 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: Gregoire Baron <baronchon@n7mm.org>
10 */
11
12#include <stdio.h>
13#include <stdlib.h>
14#include <string.h>
15#include <unistd.h>
16
17#include <linux/tc_act/tc_csum.h>
18
19#include "utils.h"
20#include "tc_util.h"
21
22static void
23explain(void)
24{
25	fprintf(stderr, "Usage: ... csum <UPDATE>\n"
26			"Where: UPDATE := <TARGET> [<UPDATE>]\n"
27			"       TARGET := { ip4h | icmp | igmp |"
28				" tcp | udp | udplite | <SWEETS> }\n"
29			"       SWEETS := { and | or | \'+\' }\n");
30}
31
32static void
33usage(void)
34{
35	explain();
36	exit(-1);
37}
38
39static int
40parse_csum_args(int *argc_p, char ***argv_p, struct tc_csum *sel)
41{
42	int argc = *argc_p;
43	char **argv = *argv_p;
44
45	if (argc <= 0)
46		return -1;
47
48	while(argc > 0) {
49		if ((matches(*argv, "iph") == 0) ||
50		    (matches(*argv, "ip4h") == 0) ||
51		    (matches(*argv, "ipv4h") == 0))
52			sel->update_flags |= TCA_CSUM_UPDATE_FLAG_IPV4HDR;
53
54		else if (matches(*argv, "icmp") == 0)
55			sel->update_flags |= TCA_CSUM_UPDATE_FLAG_ICMP;
56
57		else if (matches(*argv, "igmp") == 0)
58			sel->update_flags |= TCA_CSUM_UPDATE_FLAG_IGMP;
59
60		else if (matches(*argv, "tcp") == 0)
61			sel->update_flags |= TCA_CSUM_UPDATE_FLAG_TCP;
62
63		else if (matches(*argv, "udp") == 0)
64			sel->update_flags |= TCA_CSUM_UPDATE_FLAG_UDP;
65
66		else if (matches(*argv, "udplite") == 0)
67			sel->update_flags |= TCA_CSUM_UPDATE_FLAG_UDPLITE;
68
69		else if ((matches(*argv, "and") == 0) ||
70			 (matches(*argv, "or") == 0) ||
71			 (matches(*argv, "+") == 0))
72			; /* just ignore: ... csum iph and tcp or udp */
73		else
74			break;
75		argc--;
76		argv++;
77	}
78
79	*argc_p = argc;
80	*argv_p = argv;
81
82	return 0;
83}
84
85static int
86parse_csum(struct action_util *a, int *argc_p,
87	   char ***argv_p, int tca_id, struct nlmsghdr *n)
88{
89	struct tc_csum sel;
90
91	int argc = *argc_p;
92	char **argv = *argv_p;
93	int ok = 0;
94	struct rtattr *tail;
95
96	memset(&sel, 0, sizeof(sel));
97
98	while (argc > 0) {
99		if (matches(*argv, "csum") == 0) {
100			NEXT_ARG();
101			if (parse_csum_args(&argc, &argv, &sel)) {
102				fprintf(stderr, "Illegal csum construct (%s)\n",
103					*argv);
104				explain();
105				return -1;
106			}
107			ok++;
108			continue;
109		} else if (matches(*argv, "help") == 0) {
110			usage();
111		}
112		else {
113			break;
114		}
115	}
116
117	if (!ok) {
118		explain();
119		return -1;
120	}
121
122	if (sel.update_flags == 0) {
123		fprintf(stderr, "Illegal csum construct, empty <UPDATE> list\n");
124		return -1;
125	}
126
127	if (argc) {
128		if (matches(*argv, "reclassify") == 0) {
129			sel.action = TC_ACT_RECLASSIFY;
130			argc--;
131			argv++;
132		} else if (matches(*argv, "pipe") == 0) {
133			sel.action = TC_ACT_PIPE;
134			argc--;
135			argv++;
136		} else if (matches(*argv, "drop") == 0 ||
137			matches(*argv, "shot") == 0) {
138			sel.action = TC_ACT_SHOT;
139			argc--;
140			argv++;
141		} else if (matches(*argv, "continue") == 0) {
142			sel.action = TC_ACT_UNSPEC;
143			argc--;
144			argv++;
145		} else if (matches(*argv, "pass") == 0) {
146			sel.action = TC_ACT_OK;
147			argc--;
148			argv++;
149		}
150	}
151
152	if (argc) {
153		if (matches(*argv, "index") == 0) {
154			NEXT_ARG();
155			if (get_u32(&sel.index, *argv, 10)) {
156				fprintf(stderr, "Illegal \"index\" (%s) <csum>\n",
157					*argv);
158				return -1;
159			}
160			argc--;
161			argv++;
162		}
163	}
164
165	tail = NLMSG_TAIL(n);
166	addattr_l(n, MAX_MSG, tca_id, NULL, 0);
167	addattr_l(n, MAX_MSG, TCA_CSUM_PARMS, &sel, sizeof(sel));
168	tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
169
170	*argc_p = argc;
171	*argv_p = argv;
172
173	return 0;
174}
175
176static int
177print_csum(struct action_util *au, FILE * f, struct rtattr *arg)
178{
179	struct tc_csum *sel;
180
181	struct rtattr *tb[TCA_CSUM_MAX + 1];
182
183	char *uflag_1 = "";
184	char *uflag_2 = "";
185	char *uflag_3 = "";
186	char *uflag_4 = "";
187	char *uflag_5 = "";
188	char *uflag_6 = "";
189	SPRINT_BUF(action_buf);
190
191	int uflag_count = 0;
192
193	if (arg == NULL)
194		return -1;
195
196	parse_rtattr_nested(tb, TCA_CSUM_MAX, arg);
197
198	if (tb[TCA_CSUM_PARMS] == NULL) {
199		fprintf(f, "[NULL csum parameters]");
200		return -1;
201	}
202	sel = RTA_DATA(tb[TCA_CSUM_PARMS]);
203
204	if (sel->update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
205		uflag_1 = "iph";
206		uflag_count++;
207	}
208	#define CSUM_UFLAG_BUFFER(flag_buffer, flag_value, flag_string)	\
209		do {							\
210			if (sel->update_flags & flag_value) {		\
211				flag_buffer = uflag_count > 0 ?		\
212					", " flag_string : flag_string; \
213				uflag_count++;				\
214			}						\
215		} while(0)
216	CSUM_UFLAG_BUFFER(uflag_2, TCA_CSUM_UPDATE_FLAG_ICMP, "icmp");
217	CSUM_UFLAG_BUFFER(uflag_3, TCA_CSUM_UPDATE_FLAG_IGMP, "igmp");
218	CSUM_UFLAG_BUFFER(uflag_4, TCA_CSUM_UPDATE_FLAG_TCP, "tcp");
219	CSUM_UFLAG_BUFFER(uflag_5, TCA_CSUM_UPDATE_FLAG_UDP, "udp");
220	CSUM_UFLAG_BUFFER(uflag_6, TCA_CSUM_UPDATE_FLAG_UDPLITE, "udplite");
221	if (!uflag_count) {
222		uflag_1 = "?empty";
223	}
224
225	fprintf(f, "csum (%s%s%s%s%s%s) action %s\n",
226		uflag_1, uflag_2, uflag_3,
227		uflag_4, uflag_5, uflag_6,
228		action_n2a(sel->action, action_buf, sizeof(action_buf)));
229	fprintf(f, "\tindex %d ref %d bind %d", sel->index, sel->refcnt, sel->bindcnt);
230
231	if (show_stats) {
232		if (tb[TCA_CSUM_TM]) {
233			struct tcf_t *tm = RTA_DATA(tb[TCA_CSUM_TM]);
234			print_tm(f,tm);
235		}
236	}
237	fprintf(f, "\n");
238
239	return 0;
240}
241
242struct action_util csum_action_util = {
243	.id = "csum",
244	.parse_aopt = parse_csum,
245	.print_aopt = print_csum,
246};
247