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 #define DEBUG 0
9
10 enum {
11 O_HBH_LEN = 0,
12 O_HBH_OPTS,
13 };
14
hbh_help(void)15 static void hbh_help(void)
16 {
17 printf(
18 "hbh match options:\n"
19 "[!] --hbh-len length total length of this header\n"
20 " --hbh-opts TYPE[:LEN][,TYPE[:LEN]...] \n"
21 " Options and its length (list, max: %d)\n",
22 IP6T_OPTS_OPTSNR);
23 }
24
25 static const struct xt_option_entry hbh_opts[] = {
26 {.name = "hbh-len", .id = O_HBH_LEN, .type = XTTYPE_UINT32,
27 .flags = XTOPT_INVERT | XTOPT_PUT,
28 XTOPT_POINTER(struct ip6t_opts, hdrlen)},
29 {.name = "hbh-opts", .id = O_HBH_OPTS, .type = XTTYPE_STRING},
30 XTOPT_TABLEEND,
31 };
32
33 static uint32_t
parse_opts_num(const char * idstr,const char * typestr)34 parse_opts_num(const char *idstr, const char *typestr)
35 {
36 unsigned long int id;
37 char* ep;
38
39 id = strtoul(idstr,&ep,0) ;
40
41 if ( idstr == ep ) {
42 xtables_error(PARAMETER_PROBLEM,
43 "hbh: no valid digits in %s `%s'", typestr, idstr);
44 }
45 if ( id == ULONG_MAX && errno == ERANGE ) {
46 xtables_error(PARAMETER_PROBLEM,
47 "%s `%s' specified too big: would overflow",
48 typestr, idstr);
49 }
50 if ( *idstr != '\0' && *ep != '\0' ) {
51 xtables_error(PARAMETER_PROBLEM,
52 "hbh: error parsing %s `%s'", typestr, idstr);
53 }
54 return id;
55 }
56
57 static int
parse_options(const char * optsstr,uint16_t * opts)58 parse_options(const char *optsstr, uint16_t *opts)
59 {
60 char *buffer, *cp, *next, *range;
61 unsigned int i;
62
63 buffer = strdup(optsstr);
64 if (!buffer) xtables_error(OTHER_PROBLEM, "strdup failed");
65
66 for (cp=buffer, i=0; cp && i<IP6T_OPTS_OPTSNR; cp=next,i++)
67 {
68 next=strchr(cp, ',');
69 if (next) *next++='\0';
70 range = strchr(cp, ':');
71 if (range) {
72 if (i == IP6T_OPTS_OPTSNR-1)
73 xtables_error(PARAMETER_PROBLEM,
74 "too many ports specified");
75 *range++ = '\0';
76 }
77 opts[i] = (parse_opts_num(cp, "opt") & 0xFF) << 8;
78 if (range) {
79 if (opts[i] == 0)
80 xtables_error(PARAMETER_PROBLEM, "PAD0 has not got length");
81 opts[i] |= parse_opts_num(range, "length") & 0xFF;
82 } else {
83 opts[i] |= (0x00FF);
84 }
85
86 #if DEBUG
87 printf("opts str: %s %s\n", cp, range);
88 printf("opts opt: %04X\n", opts[i]);
89 #endif
90 }
91 if (cp) xtables_error(PARAMETER_PROBLEM, "too many addresses specified");
92
93 free(buffer);
94
95 #if DEBUG
96 printf("addr nr: %d\n", i);
97 #endif
98
99 return i;
100 }
101
hbh_parse(struct xt_option_call * cb)102 static void hbh_parse(struct xt_option_call *cb)
103 {
104 struct ip6t_opts *optinfo = cb->data;
105
106 xtables_option_parse(cb);
107 switch (cb->entry->id) {
108 case O_HBH_LEN:
109 if (cb->invert)
110 optinfo->invflags |= IP6T_OPTS_INV_LEN;
111 optinfo->flags |= IP6T_OPTS_LEN;
112 break;
113 case O_HBH_OPTS:
114 optinfo->optsnr = parse_options(cb->arg, optinfo->opts);
115 optinfo->flags |= IP6T_OPTS_OPTS;
116 break;
117 }
118 }
119
120 static void
print_options(unsigned int optsnr,uint16_t * optsp)121 print_options(unsigned int optsnr, uint16_t *optsp)
122 {
123 unsigned int i;
124
125 for(i=0; i<optsnr; i++){
126 printf("%c", (i==0)?' ':',');
127 printf("%d", (optsp[i] & 0xFF00)>>8);
128 if ((optsp[i] & 0x00FF) != 0x00FF){
129 printf(":%d", (optsp[i] & 0x00FF));
130 }
131 }
132 }
133
hbh_print(const void * ip,const struct xt_entry_match * match,int numeric)134 static void hbh_print(const void *ip, const struct xt_entry_match *match,
135 int numeric)
136 {
137 const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
138
139 printf(" hbh");
140 if (optinfo->flags & IP6T_OPTS_LEN) {
141 printf(" length");
142 printf(":%s", optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "");
143 printf("%u", optinfo->hdrlen);
144 }
145 if (optinfo->flags & IP6T_OPTS_OPTS) printf(" opts");
146 print_options(optinfo->optsnr, (uint16_t *)optinfo->opts);
147 if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
148 printf(" Unknown invflags: 0x%X",
149 optinfo->invflags & ~IP6T_OPTS_INV_MASK);
150 }
151
hbh_save(const void * ip,const struct xt_entry_match * match)152 static void hbh_save(const void *ip, const struct xt_entry_match *match)
153 {
154 const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
155
156 if (optinfo->flags & IP6T_OPTS_LEN) {
157 printf("%s --hbh-len %u",
158 (optinfo->invflags & IP6T_OPTS_INV_LEN) ? " !" : "",
159 optinfo->hdrlen);
160 }
161
162 if (optinfo->flags & IP6T_OPTS_OPTS)
163 printf(" --hbh-opts");
164 print_options(optinfo->optsnr, (uint16_t *)optinfo->opts);
165 }
166
hbh_xlate(struct xt_xlate * xl,const struct xt_xlate_mt_params * params)167 static int hbh_xlate(struct xt_xlate *xl,
168 const struct xt_xlate_mt_params *params)
169 {
170 const struct ip6t_opts *optinfo =
171 (struct ip6t_opts *)params->match->data;
172
173 if (!(optinfo->flags & IP6T_OPTS_LEN) ||
174 (optinfo->flags & IP6T_OPTS_OPTS))
175 return 0;
176
177 xt_xlate_add(xl, "hbh hdrlength %s%u",
178 (optinfo->invflags & IP6T_OPTS_INV_LEN) ? "!= " : "",
179 optinfo->hdrlen);
180
181 return 1;
182 }
183
184 static struct xtables_match hbh_mt6_reg = {
185 .name = "hbh",
186 .version = XTABLES_VERSION,
187 .family = NFPROTO_IPV6,
188 .size = XT_ALIGN(sizeof(struct ip6t_opts)),
189 .userspacesize = XT_ALIGN(sizeof(struct ip6t_opts)),
190 .help = hbh_help,
191 .print = hbh_print,
192 .save = hbh_save,
193 .x6_parse = hbh_parse,
194 .x6_options = hbh_opts,
195 .xlate = hbh_xlate,
196 };
197
198 void
_init(void)199 _init(void)
200 {
201 xtables_register_match(&hbh_mt6_reg);
202 }
203