1 /*
2 * m_skbmod.c skb modifier action module
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: J Hadi Salim (jhs@mojatatu.com)
10 *
11 */
12
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <unistd.h>
16 #include <syslog.h>
17 #include <fcntl.h>
18 #include <sys/socket.h>
19 #include <netinet/in.h>
20 #include <arpa/inet.h>
21 #include <string.h>
22 #include <linux/netdevice.h>
23
24 #include "rt_names.h"
25 #include "utils.h"
26 #include "tc_util.h"
27 #include <linux/tc_act/tc_skbmod.h>
28
skbmod_explain(void)29 static void skbmod_explain(void)
30 {
31 fprintf(stderr,
32 "Usage:... skbmod {[set <SETTABLE>] [swap <SWAPABLE>]} [CONTROL] [index INDEX]\n"
33 "where SETTABLE is: [dmac DMAC] [smac SMAC] [etype ETYPE]\n"
34 "where SWAPABLE is: \"mac\" to swap mac addresses\n"
35 "note: \"swap mac\" is done after any outstanding D/SMAC change\n"
36 "\tDMAC := 6 byte Destination MAC address\n"
37 "\tSMAC := optional 6 byte Source MAC address\n"
38 "\tETYPE := optional 16 bit ethertype\n"
39 "\tCONTROL := reclassify | pipe | drop | continue | ok |\n"
40 "\t goto chain <CHAIN_INDEX>\n"
41 "\tINDEX := skbmod index value to use\n");
42 }
43
skbmod_usage(void)44 static void skbmod_usage(void)
45 {
46 skbmod_explain();
47 exit(-1);
48 }
49
parse_skbmod(struct action_util * a,int * argc_p,char *** argv_p,int tca_id,struct nlmsghdr * n)50 static int parse_skbmod(struct action_util *a, int *argc_p, char ***argv_p,
51 int tca_id, struct nlmsghdr *n)
52 {
53 int argc = *argc_p;
54 char **argv = *argv_p;
55 int ok = 0;
56 struct tc_skbmod p;
57 struct rtattr *tail;
58 char dbuf[ETH_ALEN];
59 char sbuf[ETH_ALEN];
60 __u16 skbmod_etype = 0;
61 char *daddr = NULL;
62 char *saddr = NULL;
63
64 memset(&p, 0, sizeof(p));
65
66 if (argc <= 0)
67 return -1;
68
69 while (argc > 0) {
70 if (matches(*argv, "skbmod") == 0) {
71 NEXT_ARG();
72 continue;
73 } else if (matches(*argv, "swap") == 0) {
74 NEXT_ARG();
75 continue;
76 } else if (matches(*argv, "mac") == 0) {
77 p.flags |= SKBMOD_F_SWAPMAC;
78 ok += 1;
79 } else if (matches(*argv, "set") == 0) {
80 NEXT_ARG();
81 continue;
82 } else if (matches(*argv, "etype") == 0) {
83 NEXT_ARG();
84 if (get_u16(&skbmod_etype, *argv, 0))
85 invarg("ethertype is invalid", *argv);
86 fprintf(stderr, "skbmod etype 0x%x\n", skbmod_etype);
87 p.flags |= SKBMOD_F_ETYPE;
88 ok += 1;
89 } else if (matches(*argv, "dmac") == 0) {
90 NEXT_ARG();
91 daddr = *argv;
92 if (sscanf(daddr, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
93 dbuf, dbuf + 1, dbuf + 2,
94 dbuf + 3, dbuf + 4, dbuf + 5) != 6) {
95 fprintf(stderr, "Invalid dst mac address %s\n",
96 daddr);
97 return -1;
98 }
99 p.flags |= SKBMOD_F_DMAC;
100 fprintf(stderr, "dst MAC address <%s>\n", daddr);
101 ok += 1;
102
103 } else if (matches(*argv, "smac") == 0) {
104 NEXT_ARG();
105 saddr = *argv;
106 if (sscanf(saddr, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
107 sbuf, sbuf + 1, sbuf + 2,
108 sbuf + 3, sbuf + 4, sbuf + 5) != 6) {
109 fprintf(stderr, "Invalid smac address %s\n",
110 saddr);
111 return -1;
112 }
113 p.flags |= SKBMOD_F_SMAC;
114 fprintf(stderr, "src MAC address <%s>\n", saddr);
115 ok += 1;
116 } else if (matches(*argv, "help") == 0) {
117 skbmod_usage();
118 } else {
119 break;
120 }
121
122 argc--;
123 argv++;
124 }
125
126 parse_action_control_dflt(&argc, &argv, &p.action, false, TC_ACT_PIPE);
127
128 if (argc) {
129 if (matches(*argv, "index") == 0) {
130 NEXT_ARG();
131 if (get_u32(&p.index, *argv, 0)) {
132 fprintf(stderr, "skbmod: Illegal \"index\"\n");
133 return -1;
134 }
135 ok++;
136 argc--;
137 argv++;
138 }
139 }
140
141 if (!ok) {
142 fprintf(stderr, "skbmod requires at least one option\n");
143 skbmod_usage();
144 }
145
146 tail = NLMSG_TAIL(n);
147 addattr_l(n, MAX_MSG, tca_id, NULL, 0);
148 addattr_l(n, MAX_MSG, TCA_SKBMOD_PARMS, &p, sizeof(p));
149
150 if (daddr)
151 addattr_l(n, MAX_MSG, TCA_SKBMOD_DMAC, dbuf, ETH_ALEN);
152 if (skbmod_etype)
153 addattr16(n, MAX_MSG, TCA_SKBMOD_ETYPE, skbmod_etype);
154 if (saddr)
155 addattr_l(n, MAX_MSG, TCA_SKBMOD_SMAC, sbuf, ETH_ALEN);
156
157 tail->rta_len = (void *)NLMSG_TAIL(n) - (void *)tail;
158
159 *argc_p = argc;
160 *argv_p = argv;
161 return 0;
162 }
163
print_skbmod(struct action_util * au,FILE * f,struct rtattr * arg)164 static int print_skbmod(struct action_util *au, FILE *f, struct rtattr *arg)
165 {
166 struct tc_skbmod *p = NULL;
167 struct rtattr *tb[TCA_SKBMOD_MAX + 1];
168 __u16 skbmod_etype = 0;
169 int has_optional = 0;
170 SPRINT_BUF(b1);
171 SPRINT_BUF(b2);
172
173 if (arg == NULL)
174 return -1;
175
176 parse_rtattr_nested(tb, TCA_SKBMOD_MAX, arg);
177
178 if (tb[TCA_SKBMOD_PARMS] == NULL) {
179 fprintf(f, "[NULL skbmod parameters]");
180 return -1;
181 }
182
183 p = RTA_DATA(tb[TCA_SKBMOD_PARMS]);
184
185 fprintf(f, "skbmod ");
186 print_action_control(f, "", p->action, " ");
187
188 if (tb[TCA_SKBMOD_ETYPE]) {
189 skbmod_etype = rta_getattr_u16(tb[TCA_SKBMOD_ETYPE]);
190 has_optional = 1;
191 fprintf(f, "set etype 0x%X ", skbmod_etype);
192 }
193
194 if (has_optional)
195 fprintf(f, "\n\t ");
196
197 if (tb[TCA_SKBMOD_DMAC]) {
198 has_optional = 1;
199 fprintf(f, "set dmac %s ",
200 ll_addr_n2a(RTA_DATA(tb[TCA_SKBMOD_DMAC]),
201 RTA_PAYLOAD(tb[TCA_SKBMOD_DMAC]), 0, b1,
202 sizeof(b1)));
203
204 }
205
206 if (tb[TCA_SKBMOD_SMAC]) {
207 has_optional = 1;
208 fprintf(f, "set smac %s ",
209 ll_addr_n2a(RTA_DATA(tb[TCA_SKBMOD_SMAC]),
210 RTA_PAYLOAD(tb[TCA_SKBMOD_SMAC]), 0, b2,
211 sizeof(b2)));
212 }
213
214 if (p->flags & SKBMOD_F_SWAPMAC)
215 fprintf(f, "swap mac ");
216
217 fprintf(f, "\n\t index %u ref %d bind %d", p->index, p->refcnt,
218 p->bindcnt);
219 if (show_stats) {
220 if (tb[TCA_SKBMOD_TM]) {
221 struct tcf_t *tm = RTA_DATA(tb[TCA_SKBMOD_TM]);
222
223 print_tm(f, tm);
224 }
225 }
226
227 fprintf(f, "\n");
228
229 return 0;
230 }
231
232 struct action_util skbmod_action_util = {
233 .id = "skbmod",
234 .parse_aopt = parse_skbmod,
235 .print_aopt = print_skbmod,
236 };
237