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
22 static void
explain(void)23 explain(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
32 static void
usage(void)33 usage(void)
34 {
35 explain();
36 exit(-1);
37 }
38
39 static int
parse_csum_args(int * argc_p,char *** argv_p,struct tc_csum * sel)40 parse_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
85 static int
parse_csum(struct action_util * a,int * argc_p,char *** argv_p,int tca_id,struct nlmsghdr * n)86 parse_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
176 static int
print_csum(struct action_util * au,FILE * f,struct rtattr * arg)177 print_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
242 struct action_util csum_action_util = {
243 .id = "csum",
244 .parse_aopt = parse_csum,
245 .print_aopt = print_csum,
246 };
247