1 /* Shared library add-on to ip6tables to add AH 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/netfilter_ipv6/ip6t_ah.h>
10
11 /* Function which prints out usage message. */
12 static void
help(void)13 help(void)
14 {
15 printf(
16 "AH v%s options:\n"
17 " --ahspi [!] spi[:spi] match spi (range)\n"
18 " --ahlen [!] length total length of this header\n"
19 " --ahres check the reserved filed, too\n",
20 IPTABLES_VERSION);
21 }
22
23 static struct option opts[] = {
24 { .name = "ahspi", .has_arg = 1, .flag = 0, .val = '1' },
25 { .name = "ahlen", .has_arg = 1, .flag = 0, .val = '2' },
26 { .name = "ahres", .has_arg = 0, .flag = 0, .val = '3' },
27 { .name = 0 }
28 };
29
30 static u_int32_t
parse_ah_spi(const char * spistr,const char * typestr)31 parse_ah_spi(const char *spistr, const char *typestr)
32 {
33 unsigned long int spi;
34 char* ep;
35
36 spi = strtoul(spistr, &ep, 0);
37
38 if ( spistr == ep )
39 exit_error(PARAMETER_PROBLEM,
40 "AH no valid digits in %s `%s'", typestr, spistr);
41
42 if ( spi == ULONG_MAX && errno == ERANGE )
43 exit_error(PARAMETER_PROBLEM,
44 "%s `%s' specified too big: would overflow",
45 typestr, spistr);
46
47 if ( *spistr != '\0' && *ep != '\0' )
48 exit_error(PARAMETER_PROBLEM,
49 "AH error parsing %s `%s'", typestr, spistr);
50
51 return (u_int32_t) spi;
52 }
53
54 static void
parse_ah_spis(const char * spistring,u_int32_t * spis)55 parse_ah_spis(const char *spistring, u_int32_t *spis)
56 {
57 char *buffer;
58 char *cp;
59
60 buffer = strdup(spistring);
61 if ((cp = strchr(buffer, ':')) == NULL)
62 spis[0] = spis[1] = parse_ah_spi(buffer, "spi");
63 else {
64 *cp = '\0';
65 cp++;
66
67 spis[0] = buffer[0] ? parse_ah_spi(buffer, "spi") : 0;
68 spis[1] = cp[0] ? parse_ah_spi(cp, "spi") : 0xFFFFFFFF;
69 }
70 free(buffer);
71 }
72
73 /* Initialize the match. */
74 static void
init(struct ip6t_entry_match * m,unsigned int * nfcache)75 init(struct ip6t_entry_match *m, unsigned int *nfcache)
76 {
77 struct ip6t_ah *ahinfo = (struct ip6t_ah *)m->data;
78
79 ahinfo->spis[1] = 0xFFFFFFFF;
80 ahinfo->hdrlen = 0;
81 ahinfo->hdrres = 0;
82 }
83
84 /* Function which parses command options; returns true if it
85 ate an option */
86 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)87 parse(int c, char **argv, int invert, unsigned int *flags,
88 const struct ip6t_entry *entry,
89 unsigned int *nfcache,
90 struct ip6t_entry_match **match)
91 {
92 struct ip6t_ah *ahinfo = (struct ip6t_ah *)(*match)->data;
93
94 switch (c) {
95 case '1':
96 if (*flags & IP6T_AH_SPI)
97 exit_error(PARAMETER_PROBLEM,
98 "Only one `--ahspi' allowed");
99 check_inverse(optarg, &invert, &optind, 0);
100 parse_ah_spis(argv[optind-1], ahinfo->spis);
101 if (invert)
102 ahinfo->invflags |= IP6T_AH_INV_SPI;
103 *flags |= IP6T_AH_SPI;
104 break;
105 case '2':
106 if (*flags & IP6T_AH_LEN)
107 exit_error(PARAMETER_PROBLEM,
108 "Only one `--ahlen' allowed");
109 check_inverse(optarg, &invert, &optind, 0);
110 ahinfo->hdrlen = parse_ah_spi(argv[optind-1], "length");
111 if (invert)
112 ahinfo->invflags |= IP6T_AH_INV_LEN;
113 *flags |= IP6T_AH_LEN;
114 break;
115 case '3':
116 if (*flags & IP6T_AH_RES)
117 exit_error(PARAMETER_PROBLEM,
118 "Only one `--ahres' allowed");
119 ahinfo->hdrres = 1;
120 *flags |= IP6T_AH_RES;
121 break;
122 default:
123 return 0;
124 }
125
126 return 1;
127 }
128
129 /* Final check; we don't care. */
130 static void
final_check(unsigned int flags)131 final_check(unsigned int flags)
132 {
133 }
134
135 static void
print_spis(const char * name,u_int32_t min,u_int32_t max,int invert)136 print_spis(const char *name, u_int32_t min, u_int32_t max,
137 int invert)
138 {
139 const char *inv = invert ? "!" : "";
140
141 if (min != 0 || max != 0xFFFFFFFF || invert) {
142 if (min == max)
143 printf("%s:%s%u ", name, inv, min);
144 else
145 printf("%ss:%s%u:%u ", name, inv, min, max);
146 }
147 }
148
149 static void
print_len(const char * name,u_int32_t len,int invert)150 print_len(const char *name, u_int32_t len, int invert)
151 {
152 const char *inv = invert ? "!" : "";
153
154 if (len != 0 || invert)
155 printf("%s:%s%u ", name, inv, len);
156 }
157
158 /* Prints out the union ip6t_matchinfo. */
159 static void
print(const struct ip6t_ip6 * ip,const struct ip6t_entry_match * match,int numeric)160 print(const struct ip6t_ip6 *ip,
161 const struct ip6t_entry_match *match, int numeric)
162 {
163 const struct ip6t_ah *ah = (struct ip6t_ah *)match->data;
164
165 printf("ah ");
166 print_spis("spi", ah->spis[0], ah->spis[1],
167 ah->invflags & IP6T_AH_INV_SPI);
168 print_len("length", ah->hdrlen,
169 ah->invflags & IP6T_AH_INV_LEN);
170
171 if (ah->hdrres)
172 printf("reserved ");
173
174 if (ah->invflags & ~IP6T_AH_INV_MASK)
175 printf("Unknown invflags: 0x%X ",
176 ah->invflags & ~IP6T_AH_INV_MASK);
177 }
178
179 /* Saves the union ip6t_matchinfo in parsable form to stdout. */
save(const struct ip6t_ip6 * ip,const struct ip6t_entry_match * match)180 static void save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match)
181 {
182 const struct ip6t_ah *ahinfo = (struct ip6t_ah *)match->data;
183
184 if (!(ahinfo->spis[0] == 0
185 && ahinfo->spis[1] == 0xFFFFFFFF)) {
186 printf("--ahspi %s",
187 (ahinfo->invflags & IP6T_AH_INV_SPI) ? "! " : "");
188 if (ahinfo->spis[0]
189 != ahinfo->spis[1])
190 printf("%u:%u ",
191 ahinfo->spis[0],
192 ahinfo->spis[1]);
193 else
194 printf("%u ",
195 ahinfo->spis[0]);
196 }
197
198 if (ahinfo->hdrlen != 0 || (ahinfo->invflags & IP6T_AH_INV_LEN) ) {
199 printf("--ahlen %s%u ",
200 (ahinfo->invflags & IP6T_AH_INV_LEN) ? "! " : "",
201 ahinfo->hdrlen);
202 }
203
204 if (ahinfo->hdrres != 0 )
205 printf("--ahres ");
206 }
207
208 static
209 struct ip6tables_match ah = {
210 .name = "ah",
211 .version = IPTABLES_VERSION,
212 .size = IP6T_ALIGN(sizeof(struct ip6t_ah)),
213 .userspacesize = IP6T_ALIGN(sizeof(struct ip6t_ah)),
214 .help = &help,
215 .init = &init,
216 .parse = &parse,
217 .final_check = &final_check,
218 .print = &print,
219 .save = &save,
220 .extra_opts = opts
221 };
222
223 void
_init(void)224 _init(void)
225 {
226 register_match6(&ah);
227 }
228