1 /* Shared library add-on to iptables to add ESP 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 <iptables.h>
9 #include <linux/netfilter_ipv4/ipt_esp.h>
10
11 /* Function which prints out usage message. */
12 static void
help(void)13 help(void)
14 {
15 printf(
16 "ESP v%s options:\n"
17 " --espspi [!] spi[:spi]\n"
18 " match spi (range)\n",
19 IPTABLES_VERSION);
20 }
21
22 static struct option opts[] = {
23 { "espspi", 1, 0, '1' },
24 {0}
25 };
26
27 static u_int32_t
parse_esp_spi(const char * spistr)28 parse_esp_spi(const char *spistr)
29 {
30 unsigned long int spi;
31 char* ep;
32
33 spi = strtoul(spistr,&ep,0) ;
34
35 if ( spistr == ep ) {
36 exit_error(PARAMETER_PROBLEM,
37 "ESP no valid digits in spi `%s'", spistr);
38 }
39 if ( spi == ULONG_MAX && errno == ERANGE ) {
40 exit_error(PARAMETER_PROBLEM,
41 "spi `%s' specified too big: would overflow", spistr);
42 }
43 if ( *spistr != '\0' && *ep != '\0' ) {
44 exit_error(PARAMETER_PROBLEM,
45 "ESP error parsing spi `%s'", spistr);
46 }
47 return (u_int32_t) spi;
48 }
49
50 static void
parse_esp_spis(const char * spistring,u_int32_t * spis)51 parse_esp_spis(const char *spistring, u_int32_t *spis)
52 {
53 char *buffer;
54 char *cp;
55
56 buffer = strdup(spistring);
57 if ((cp = strchr(buffer, ':')) == NULL)
58 spis[0] = spis[1] = parse_esp_spi(buffer);
59 else {
60 *cp = '\0';
61 cp++;
62
63 spis[0] = buffer[0] ? parse_esp_spi(buffer) : 0;
64 spis[1] = cp[0] ? parse_esp_spi(cp) : 0xFFFFFFFF;
65 if (spis[0] > spis[1])
66 exit_error(PARAMETER_PROBLEM,
67 "Invalid ESP spi range: %s", spistring);
68 }
69 free(buffer);
70 }
71
72 /* Initialize the match. */
73 static void
init(struct ipt_entry_match * m,unsigned int * nfcache)74 init(struct ipt_entry_match *m, unsigned int *nfcache)
75 {
76 struct ipt_esp *espinfo = (struct ipt_esp *)m->data;
77
78 espinfo->spis[1] = 0xFFFFFFFF;
79 }
80
81 #define ESP_SPI 0x01
82
83 /* Function which parses command options; returns true if it
84 ate an option */
85 static int
parse(int c,char ** argv,int invert,unsigned int * flags,const struct ipt_entry * entry,unsigned int * nfcache,struct ipt_entry_match ** match)86 parse(int c, char **argv, int invert, unsigned int *flags,
87 const struct ipt_entry *entry,
88 unsigned int *nfcache,
89 struct ipt_entry_match **match)
90 {
91 struct ipt_esp *espinfo = (struct ipt_esp *)(*match)->data;
92
93 switch (c) {
94 case '1':
95 if (*flags & ESP_SPI)
96 exit_error(PARAMETER_PROBLEM,
97 "Only one `--espspi' allowed");
98 check_inverse(optarg, &invert, &optind, 0);
99 parse_esp_spis(argv[optind-1], espinfo->spis);
100 if (invert)
101 espinfo->invflags |= IPT_ESP_INV_SPI;
102 *flags |= ESP_SPI;
103 break;
104 default:
105 return 0;
106 }
107
108 return 1;
109 }
110
111 /* Final check; we don't care. */
112 static void
final_check(unsigned int flags)113 final_check(unsigned int flags)
114 {
115 }
116
117 static void
print_spis(const char * name,u_int32_t min,u_int32_t max,int invert)118 print_spis(const char *name, u_int32_t min, u_int32_t max,
119 int invert)
120 {
121 const char *inv = invert ? "!" : "";
122
123 if (min != 0 || max != 0xFFFFFFFF || invert) {
124 printf("%s", name);
125 if (min == max) {
126 printf(":%s", inv);
127 printf("%u", min);
128 } else {
129 printf("s:%s", inv);
130 printf("%u",min);
131 printf(":");
132 printf("%u",max);
133 }
134 printf(" ");
135 }
136 }
137
138 /* Prints out the union ipt_matchinfo. */
139 static void
print(const struct ipt_ip * ip,const struct ipt_entry_match * match,int numeric)140 print(const struct ipt_ip *ip,
141 const struct ipt_entry_match *match, int numeric)
142 {
143 const struct ipt_esp *esp = (struct ipt_esp *)match->data;
144
145 printf("esp ");
146 print_spis("spi", esp->spis[0], esp->spis[1],
147 esp->invflags & IPT_ESP_INV_SPI);
148 if (esp->invflags & ~IPT_ESP_INV_MASK)
149 printf("Unknown invflags: 0x%X ",
150 esp->invflags & ~IPT_ESP_INV_MASK);
151 }
152
153 /* Saves the union ipt_matchinfo in parsable form to stdout. */
save(const struct ipt_ip * ip,const struct ipt_entry_match * match)154 static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
155 {
156 const struct ipt_esp *espinfo = (struct ipt_esp *)match->data;
157
158 if (!(espinfo->spis[0] == 0
159 && espinfo->spis[1] == 0xFFFFFFFF)) {
160 printf("--espspi %s",
161 (espinfo->invflags & IPT_ESP_INV_SPI) ? "! " : "");
162 if (espinfo->spis[0]
163 != espinfo->spis[1])
164 printf("%u:%u ",
165 espinfo->spis[0],
166 espinfo->spis[1]);
167 else
168 printf("%u ",
169 espinfo->spis[0]);
170 }
171
172 }
173
174 static struct iptables_match esp = {
175 .next = NULL,
176 .name = "esp",
177 .version = IPTABLES_VERSION,
178 .size = IPT_ALIGN(sizeof(struct ipt_esp)),
179 .userspacesize = IPT_ALIGN(sizeof(struct ipt_esp)),
180 .help = &help,
181 .init = &init,
182 .parse = &parse,
183 .final_check = &final_check,
184 .print = &print,
185 .save = &save,
186 .extra_opts = opts
187 };
188
189 void
ipt_esp_init(void)190 ipt_esp_init(void)
191 {
192 register_match(&esp);
193 }
194