Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* Kernel module to match one of a list of TCP/UDP ports: ports are in |
| 2 | the same place so we can treat them as equal. */ |
| 3 | |
| 4 | /* (C) 1999-2001 Paul `Rusty' Russell |
| 5 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/types.h> |
| 14 | #include <linux/udp.h> |
| 15 | #include <linux/skbuff.h> |
| 16 | |
| 17 | #include <linux/netfilter_ipv4/ipt_multiport.h> |
| 18 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 19 | |
| 20 | MODULE_LICENSE("GPL"); |
| 21 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); |
| 22 | MODULE_DESCRIPTION("iptables multiple port match module"); |
| 23 | |
| 24 | #if 0 |
| 25 | #define duprintf(format, args...) printk(format , ## args) |
| 26 | #else |
| 27 | #define duprintf(format, args...) |
| 28 | #endif |
| 29 | |
| 30 | /* Returns 1 if the port is matched by the test, 0 otherwise. */ |
| 31 | static inline int |
| 32 | ports_match(const u_int16_t *portlist, enum ipt_multiport_flags flags, |
| 33 | u_int8_t count, u_int16_t src, u_int16_t dst) |
| 34 | { |
| 35 | unsigned int i; |
| 36 | for (i=0; i<count; i++) { |
| 37 | if (flags != IPT_MULTIPORT_DESTINATION |
| 38 | && portlist[i] == src) |
| 39 | return 1; |
| 40 | |
| 41 | if (flags != IPT_MULTIPORT_SOURCE |
| 42 | && portlist[i] == dst) |
| 43 | return 1; |
| 44 | } |
| 45 | |
| 46 | return 0; |
| 47 | } |
| 48 | |
| 49 | /* Returns 1 if the port is matched by the test, 0 otherwise. */ |
| 50 | static inline int |
| 51 | ports_match_v1(const struct ipt_multiport_v1 *minfo, |
| 52 | u_int16_t src, u_int16_t dst) |
| 53 | { |
| 54 | unsigned int i; |
| 55 | u_int16_t s, e; |
| 56 | |
| 57 | for (i=0; i < minfo->count; i++) { |
| 58 | s = minfo->ports[i]; |
| 59 | |
| 60 | if (minfo->pflags[i]) { |
| 61 | /* range port matching */ |
| 62 | e = minfo->ports[++i]; |
| 63 | duprintf("src or dst matches with %d-%d?\n", s, e); |
| 64 | |
| 65 | if (minfo->flags == IPT_MULTIPORT_SOURCE |
| 66 | && src >= s && src <= e) |
| 67 | return 1 ^ minfo->invert; |
| 68 | if (minfo->flags == IPT_MULTIPORT_DESTINATION |
| 69 | && dst >= s && dst <= e) |
| 70 | return 1 ^ minfo->invert; |
| 71 | if (minfo->flags == IPT_MULTIPORT_EITHER |
| 72 | && ((dst >= s && dst <= e) |
| 73 | || (src >= s && src <= e))) |
| 74 | return 1 ^ minfo->invert; |
| 75 | } else { |
| 76 | /* exact port matching */ |
| 77 | duprintf("src or dst matches with %d?\n", s); |
| 78 | |
| 79 | if (minfo->flags == IPT_MULTIPORT_SOURCE |
| 80 | && src == s) |
| 81 | return 1 ^ minfo->invert; |
| 82 | if (minfo->flags == IPT_MULTIPORT_DESTINATION |
| 83 | && dst == s) |
| 84 | return 1 ^ minfo->invert; |
| 85 | if (minfo->flags == IPT_MULTIPORT_EITHER |
| 86 | && (src == s || dst == s)) |
| 87 | return 1 ^ minfo->invert; |
| 88 | } |
| 89 | } |
| 90 | |
| 91 | return minfo->invert; |
| 92 | } |
| 93 | |
| 94 | static int |
| 95 | match(const struct sk_buff *skb, |
| 96 | const struct net_device *in, |
| 97 | const struct net_device *out, |
| 98 | const void *matchinfo, |
| 99 | int offset, |
| 100 | int *hotdrop) |
| 101 | { |
| 102 | u16 _ports[2], *pptr; |
| 103 | const struct ipt_multiport *multiinfo = matchinfo; |
| 104 | |
| 105 | if (offset) |
| 106 | return 0; |
| 107 | |
| 108 | pptr = skb_header_pointer(skb, skb->nh.iph->ihl * 4, |
| 109 | sizeof(_ports), _ports); |
| 110 | if (pptr == NULL) { |
| 111 | /* We've been asked to examine this packet, and we |
| 112 | * can't. Hence, no choice but to drop. |
| 113 | */ |
| 114 | duprintf("ipt_multiport:" |
| 115 | " Dropping evil offset=0 tinygram.\n"); |
| 116 | *hotdrop = 1; |
| 117 | return 0; |
| 118 | } |
| 119 | |
| 120 | return ports_match(multiinfo->ports, |
| 121 | multiinfo->flags, multiinfo->count, |
| 122 | ntohs(pptr[0]), ntohs(pptr[1])); |
| 123 | } |
| 124 | |
| 125 | static int |
| 126 | match_v1(const struct sk_buff *skb, |
| 127 | const struct net_device *in, |
| 128 | const struct net_device *out, |
| 129 | const void *matchinfo, |
| 130 | int offset, |
| 131 | int *hotdrop) |
| 132 | { |
| 133 | u16 _ports[2], *pptr; |
| 134 | const struct ipt_multiport_v1 *multiinfo = matchinfo; |
| 135 | |
| 136 | if (offset) |
| 137 | return 0; |
| 138 | |
| 139 | pptr = skb_header_pointer(skb, skb->nh.iph->ihl * 4, |
| 140 | sizeof(_ports), _ports); |
| 141 | if (pptr == NULL) { |
| 142 | /* We've been asked to examine this packet, and we |
| 143 | * can't. Hence, no choice but to drop. |
| 144 | */ |
| 145 | duprintf("ipt_multiport:" |
| 146 | " Dropping evil offset=0 tinygram.\n"); |
| 147 | *hotdrop = 1; |
| 148 | return 0; |
| 149 | } |
| 150 | |
| 151 | return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1])); |
| 152 | } |
| 153 | |
| 154 | /* Called when user tries to insert an entry of this type. */ |
| 155 | static int |
| 156 | checkentry(const char *tablename, |
| 157 | const struct ipt_ip *ip, |
| 158 | void *matchinfo, |
| 159 | unsigned int matchsize, |
| 160 | unsigned int hook_mask) |
| 161 | { |
| 162 | return (matchsize == IPT_ALIGN(sizeof(struct ipt_multiport))); |
| 163 | } |
| 164 | |
| 165 | static int |
| 166 | checkentry_v1(const char *tablename, |
| 167 | const struct ipt_ip *ip, |
| 168 | void *matchinfo, |
| 169 | unsigned int matchsize, |
| 170 | unsigned int hook_mask) |
| 171 | { |
| 172 | return (matchsize == IPT_ALIGN(sizeof(struct ipt_multiport_v1))); |
| 173 | } |
| 174 | |
| 175 | static struct ipt_match multiport_match = { |
| 176 | .name = "multiport", |
| 177 | .revision = 0, |
| 178 | .match = &match, |
| 179 | .checkentry = &checkentry, |
| 180 | .me = THIS_MODULE, |
| 181 | }; |
| 182 | |
| 183 | static struct ipt_match multiport_match_v1 = { |
| 184 | .name = "multiport", |
| 185 | .revision = 1, |
| 186 | .match = &match_v1, |
| 187 | .checkentry = &checkentry_v1, |
| 188 | .me = THIS_MODULE, |
| 189 | }; |
| 190 | |
| 191 | static int __init init(void) |
| 192 | { |
| 193 | int err; |
| 194 | |
| 195 | err = ipt_register_match(&multiport_match); |
| 196 | if (!err) { |
| 197 | err = ipt_register_match(&multiport_match_v1); |
| 198 | if (err) |
| 199 | ipt_unregister_match(&multiport_match); |
| 200 | } |
| 201 | |
| 202 | return err; |
| 203 | } |
| 204 | |
| 205 | static void __exit fini(void) |
| 206 | { |
| 207 | ipt_unregister_match(&multiport_match); |
| 208 | ipt_unregister_match(&multiport_match_v1); |
| 209 | } |
| 210 | |
| 211 | module_init(init); |
| 212 | module_exit(fini); |