1 /* Shared library add-on to ip6tables to add Hop-by-Hop and Dst headers support. */
2 #include <stdio.h>
3 #include <netdb.h>
4 #include <string.h>
5 #include <stdlib.h>
6 #include <getopt.h>
7 #include <errno.h>
8 #include <ip6tables.h>
9 /*#include <linux/in6.h>*/
10 #include <linux/netfilter_ipv6/ip6t_opts.h>
11 #include <sys/types.h>
12 #include <sys/socket.h>
13 #include <arpa/inet.h>
14
15 #define DEBUG 0
16 #define HOPBYHOP 1
17 #define UNAME (HOPBYHOP ? "HBH" : "DST")
18 #define LNAME (HOPBYHOP ? "hbh" : "dst")
19
20 /* Function which prints out usage message. */
21 static void
help(void)22 help(void)
23 {
24 printf(
25 "%s v%s options:\n"
26 " --%s-len [!] length total length of this header\n"
27 " --%s-opts TYPE[:LEN][,TYPE[:LEN]...] \n"
28 " Options and its length (list, max: %d)\n",
29 UNAME , IPTABLES_VERSION, LNAME, LNAME, IP6T_OPTS_OPTSNR);
30 }
31
32 #if HOPBYHOP
33 static struct option opts[] = {
34 { "hbh-len", 1, 0, '1' },
35 { "hbh-opts", 1, 0, '2' },
36 { "hbh-not-strict", 1, 0, '3' },
37 {0}
38 };
39 #else
40 static struct option opts[] = {
41 { "dst-len", 1, 0, '1' },
42 { "dst-opts", 1, 0, '2' },
43 { "dst-not-strict", 1, 0, '3' },
44 {0}
45 };
46 #endif
47
48 static u_int32_t
parse_opts_num(const char * idstr,const char * typestr)49 parse_opts_num(const char *idstr, const char *typestr)
50 {
51 unsigned long int id;
52 char* ep;
53
54 id = strtoul(idstr,&ep,0) ;
55
56 if ( idstr == ep ) {
57 exit_error(PARAMETER_PROBLEM,
58 "%s no valid digits in %s `%s'", UNAME, typestr, idstr);
59 }
60 if ( id == ULONG_MAX && errno == ERANGE ) {
61 exit_error(PARAMETER_PROBLEM,
62 "%s `%s' specified too big: would overflow",
63 typestr, idstr);
64 }
65 if ( *idstr != '\0' && *ep != '\0' ) {
66 exit_error(PARAMETER_PROBLEM,
67 "%s error parsing %s `%s'", UNAME, typestr, idstr);
68 }
69 return (u_int32_t) id;
70 }
71
72 static int
parse_options(const char * optsstr,u_int16_t * opts)73 parse_options(const char *optsstr, u_int16_t *opts)
74 {
75 char *buffer, *cp, *next, *range;
76 unsigned int i;
77
78 buffer = strdup(optsstr);
79 if (!buffer) exit_error(OTHER_PROBLEM, "strdup failed");
80
81 for (cp=buffer, i=0; cp && i<IP6T_OPTS_OPTSNR; cp=next,i++)
82 {
83 next=strchr(cp, ',');
84 if (next) *next++='\0';
85 range = strchr(cp, ':');
86 if (range) {
87 if (i == IP6T_OPTS_OPTSNR-1)
88 exit_error(PARAMETER_PROBLEM,
89 "too many ports specified");
90 *range++ = '\0';
91 }
92 opts[i] = (u_int16_t)((parse_opts_num(cp,"opt") & 0x000000FF)<<8);
93 if (range) {
94 if (opts[i] == 0)
95 exit_error(PARAMETER_PROBLEM, "PAD0 hasn't got length");
96 opts[i] |= (u_int16_t)(parse_opts_num(range,"length") &
97 0x000000FF);
98 } else {
99 opts[i] |= (0x00FF);
100 }
101
102 #if DEBUG
103 printf("opts str: %s %s\n", cp, range);
104 printf("opts opt: %04X\n", opts[i]);
105 #endif
106 }
107 if (cp) exit_error(PARAMETER_PROBLEM, "too many addresses specified");
108
109 free(buffer);
110
111 #if DEBUG
112 printf("addr nr: %d\n", i);
113 #endif
114
115 return i;
116 }
117
118 /* Initialize the match. */
119 static void
init(struct ip6t_entry_match * m,unsigned int * nfcache)120 init(struct ip6t_entry_match *m, unsigned int *nfcache)
121 {
122 struct ip6t_opts *optinfo = (struct ip6t_opts *)m->data;
123
124 optinfo->hdrlen = 0;
125 optinfo->flags = 0;
126 optinfo->invflags = 0;
127 optinfo->optsnr = 0;
128 }
129
130 /* Function which parses command options; returns true if it
131 ate an option */
132 static int
parse(int c,char ** argv,int invert,unsigned int * flags,const struct ip6t_entry * entry,unsigned int * nfcache,struct ip6t_entry_match ** match)133 parse(int c, char **argv, int invert, unsigned int *flags,
134 const struct ip6t_entry *entry,
135 unsigned int *nfcache,
136 struct ip6t_entry_match **match)
137 {
138 struct ip6t_opts *optinfo = (struct ip6t_opts *)(*match)->data;
139
140 switch (c) {
141 case '1':
142 if (*flags & IP6T_OPTS_LEN)
143 exit_error(PARAMETER_PROBLEM,
144 "Only one `--%s-len' allowed", LNAME);
145 check_inverse(optarg, &invert, &optind, 0);
146 optinfo->hdrlen = parse_opts_num(argv[optind-1], "length");
147 if (invert)
148 optinfo->invflags |= IP6T_OPTS_INV_LEN;
149 optinfo->flags |= IP6T_OPTS_LEN;
150 *flags |= IP6T_OPTS_LEN;
151 break;
152 case '2':
153 if (*flags & IP6T_OPTS_OPTS)
154 exit_error(PARAMETER_PROBLEM,
155 "Only one `--%s-opts' allowed", LNAME);
156 check_inverse(optarg, &invert, &optind, 0);
157 if (invert)
158 exit_error(PARAMETER_PROBLEM,
159 " '!' not allowed with `--%s-opts'", LNAME);
160 optinfo->optsnr = parse_options(argv[optind-1], optinfo->opts);
161 optinfo->flags |= IP6T_OPTS_OPTS;
162 *flags |= IP6T_OPTS_OPTS;
163 break;
164 case '3':
165 if (*flags & IP6T_OPTS_NSTRICT)
166 exit_error(PARAMETER_PROBLEM,
167 "Only one `--%s-not-strict' allowed", LNAME);
168 if ( !(*flags & IP6T_OPTS_OPTS) )
169 exit_error(PARAMETER_PROBLEM,
170 "`--%s-opts ...' required before `--%s-not-strict'", LNAME, LNAME);
171 optinfo->flags |= IP6T_OPTS_NSTRICT;
172 *flags |= IP6T_OPTS_NSTRICT;
173 break;
174 default:
175 return 0;
176 }
177
178 return 1;
179 }
180
181 /* Final check; we don't care. */
182 static void
final_check(unsigned int flags)183 final_check(unsigned int flags)
184 {
185 }
186
187 static void
print_options(int optsnr,u_int16_t * optsp)188 print_options(int optsnr, u_int16_t *optsp)
189 {
190 unsigned int i;
191
192 for(i=0; i<optsnr; i++){
193 printf("%d", (optsp[i] & 0xFF00)>>8);
194 if ((optsp[i] & 0x00FF) != 0x00FF){
195 printf(":%d", (optsp[i] & 0x00FF));
196 }
197 printf("%c", (i!=optsnr-1)?',':' ');
198 }
199 }
200
201 /* Prints out the union ip6t_matchinfo. */
202 static void
print(const struct ip6t_ip6 * ip,const struct ip6t_entry_match * match,int numeric)203 print(const struct ip6t_ip6 *ip,
204 const struct ip6t_entry_match *match, int numeric)
205 {
206 const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
207
208 printf("%s ", LNAME);
209 if (optinfo->flags & IP6T_OPTS_LEN) {
210 printf("length");
211 printf(":%s", optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "");
212 printf("%u", optinfo->hdrlen);
213 printf(" ");
214 }
215 if (optinfo->flags & IP6T_OPTS_OPTS) printf("opts ");
216 print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
217 if (optinfo->flags & IP6T_OPTS_NSTRICT) printf("not-strict ");
218 if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
219 printf("Unknown invflags: 0x%X ",
220 optinfo->invflags & ~IP6T_OPTS_INV_MASK);
221 }
222
223 /* Saves the union ip6t_matchinfo in parsable form to stdout. */
save(const struct ip6t_ip6 * ip,const struct ip6t_entry_match * match)224 static void save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match)
225 {
226 const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
227
228 if (optinfo->flags & IP6T_OPTS_LEN) {
229 printf("--%s-len %s%u ", LNAME,
230 (optinfo->invflags & IP6T_OPTS_INV_LEN) ? "! " : "",
231 optinfo->hdrlen);
232 }
233
234 if (optinfo->flags & IP6T_OPTS_OPTS) printf("--%s-opts ", LNAME);
235 print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
236 if (optinfo->flags & IP6T_OPTS_NSTRICT) printf("--%s-not-strict ", LNAME);
237
238 }
239
240 static struct ip6tables_match optstruct = {
241 #if HOPBYHOP
242 .name = "hbh",
243 #else
244 .name = "dst",
245 #endif
246 .version = IPTABLES_VERSION,
247 .size = IP6T_ALIGN(sizeof(struct ip6t_opts)),
248 .userspacesize = IP6T_ALIGN(sizeof(struct ip6t_opts)),
249 .help = &help,
250 .init = &init,
251 .parse = &parse,
252 .final_check = &final_check,
253 .print = &print,
254 .save = &save,
255 .extra_opts = opts,
256 };
257
258 void
_init(void)259 _init(void)
260 {
261 register_match6(&optstruct);
262 }
263