1 #include <stdio.h>
2 #include <string.h>
3 #include <stdlib.h>
4 #include <errno.h>
5 #include <xtables.h>
6 #include <linux/netfilter_ipv6/ip6t_opts.h>
7
8 enum {
9 O_DSTLEN = 0,
10 O_DSTOPTS,
11 };
12
dst_help(void)13 static void dst_help(void)
14 {
15 printf(
16 "dst match options:\n"
17 "[!] --dst-len length total length of this header\n"
18 " --dst-opts TYPE[:LEN][,TYPE[:LEN]...]\n"
19 " Options and its length (list, max: %d)\n",
20 IP6T_OPTS_OPTSNR);
21 }
22
23 static const struct xt_option_entry dst_opts[] = {
24 {.name = "dst-len", .id = O_DSTLEN, .type = XTTYPE_UINT32,
25 .flags = XTOPT_INVERT | XTOPT_PUT,
26 XTOPT_POINTER(struct ip6t_opts, hdrlen)},
27 {.name = "dst-opts", .id = O_DSTOPTS, .type = XTTYPE_STRING},
28 XTOPT_TABLEEND,
29 };
30
31 static uint32_t
parse_opts_num(const char * idstr,const char * typestr)32 parse_opts_num(const char *idstr, const char *typestr)
33 {
34 unsigned long int id;
35 char* ep;
36
37 id = strtoul(idstr, &ep, 0);
38
39 if ( idstr == ep ) {
40 xtables_error(PARAMETER_PROBLEM,
41 "dst: no valid digits in %s `%s'", typestr, idstr);
42 }
43 if ( id == ULONG_MAX && errno == ERANGE ) {
44 xtables_error(PARAMETER_PROBLEM,
45 "%s `%s' specified too big: would overflow",
46 typestr, idstr);
47 }
48 if ( *idstr != '\0' && *ep != '\0' ) {
49 xtables_error(PARAMETER_PROBLEM,
50 "dst: error parsing %s `%s'", typestr, idstr);
51 }
52 return id;
53 }
54
55 static int
parse_options(const char * optsstr,uint16_t * opts)56 parse_options(const char *optsstr, uint16_t *opts)
57 {
58 char *buffer, *cp, *next, *range;
59 unsigned int i;
60
61 buffer = strdup(optsstr);
62 if (!buffer)
63 xtables_error(OTHER_PROBLEM, "strdup failed");
64
65 for (cp = buffer, i = 0; cp && i < IP6T_OPTS_OPTSNR; cp = next, i++)
66 {
67 next = strchr(cp, ',');
68
69 if (next)
70 *next++='\0';
71
72 range = strchr(cp, ':');
73
74 if (range) {
75 if (i == IP6T_OPTS_OPTSNR-1)
76 xtables_error(PARAMETER_PROBLEM,
77 "too many ports specified");
78 *range++ = '\0';
79 }
80
81 opts[i] = (parse_opts_num(cp, "opt") & 0xFF) << 8;
82 if (range) {
83 if (opts[i] == 0)
84 xtables_error(PARAMETER_PROBLEM,
85 "PAD0 hasn't got length");
86 opts[i] |= parse_opts_num(range, "length") & 0xFF;
87 } else
88 opts[i] |= (0x00FF);
89
90 #ifdef DEBUG
91 printf("opts str: %s %s\n", cp, range);
92 printf("opts opt: %04X\n", opts[i]);
93 #endif
94 }
95
96 if (cp)
97 xtables_error(PARAMETER_PROBLEM, "too many addresses specified");
98
99 free(buffer);
100
101 #ifdef DEBUG
102 printf("addr nr: %d\n", i);
103 #endif
104
105 return i;
106 }
107
dst_parse(struct xt_option_call * cb)108 static void dst_parse(struct xt_option_call *cb)
109 {
110 struct ip6t_opts *optinfo = cb->data;
111
112 xtables_option_parse(cb);
113 switch (cb->entry->id) {
114 case O_DSTLEN:
115 if (cb->invert)
116 optinfo->invflags |= IP6T_OPTS_INV_LEN;
117 optinfo->flags |= IP6T_OPTS_LEN;
118 break;
119 case O_DSTOPTS:
120 optinfo->optsnr = parse_options(cb->arg, optinfo->opts);
121 optinfo->flags |= IP6T_OPTS_OPTS;
122 break;
123 }
124 }
125
126 static void
print_options(unsigned int optsnr,uint16_t * optsp)127 print_options(unsigned int optsnr, uint16_t *optsp)
128 {
129 unsigned int i;
130
131 printf(" ");
132 for(i = 0; i < optsnr; i++) {
133 printf("%d", (optsp[i] & 0xFF00) >> 8);
134
135 if ((optsp[i] & 0x00FF) != 0x00FF)
136 printf(":%d", (optsp[i] & 0x00FF));
137
138 printf("%c", (i != optsnr - 1) ? ',' : ' ');
139 }
140 }
141
dst_print(const void * ip,const struct xt_entry_match * match,int numeric)142 static void dst_print(const void *ip, const struct xt_entry_match *match,
143 int numeric)
144 {
145 const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
146
147 printf(" dst");
148 if (optinfo->flags & IP6T_OPTS_LEN)
149 printf(" length:%s%u",
150 optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "",
151 optinfo->hdrlen);
152
153 if (optinfo->flags & IP6T_OPTS_OPTS)
154 printf(" opts");
155
156 print_options(optinfo->optsnr, (uint16_t *)optinfo->opts);
157
158 if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
159 printf(" Unknown invflags: 0x%X",
160 optinfo->invflags & ~IP6T_OPTS_INV_MASK);
161 }
162
dst_save(const void * ip,const struct xt_entry_match * match)163 static void dst_save(const void *ip, const struct xt_entry_match *match)
164 {
165 const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
166
167 if (optinfo->flags & IP6T_OPTS_LEN) {
168 printf("%s --dst-len %u",
169 (optinfo->invflags & IP6T_OPTS_INV_LEN) ? " !" : "",
170 optinfo->hdrlen);
171 }
172
173 if (optinfo->flags & IP6T_OPTS_OPTS)
174 printf(" --dst-opts");
175
176 print_options(optinfo->optsnr, (uint16_t *)optinfo->opts);
177 }
178
179 static struct xtables_match dst_mt6_reg = {
180 .name = "dst",
181 .version = XTABLES_VERSION,
182 .family = NFPROTO_IPV6,
183 .size = XT_ALIGN(sizeof(struct ip6t_opts)),
184 .userspacesize = XT_ALIGN(sizeof(struct ip6t_opts)),
185 .help = dst_help,
186 .print = dst_print,
187 .save = dst_save,
188 .x6_parse = dst_parse,
189 .x6_options = dst_opts,
190 };
191
192 void
_init(void)193 _init(void)
194 {
195 xtables_register_match(&dst_mt6_reg);
196 }
197