Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 | /* Compatibility framework for ipchains and ipfwadm support; designed
to look as much like the 2.2 infrastructure as possible. */
struct notifier_block;
#include <linux/netfilter_ipv4.h>
#include <linux/ip.h>
#include <net/icmp.h>
#include <linux/if.h>
#include <linux/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <net/ip.h>
#include <net/route.h>
#include <linux/netfilter_ipv4/compat_firewall.h>
#include <linux/netfilter_ipv4/ip_conntrack.h>
#include <linux/netfilter_ipv4/ip_conntrack_core.h>
/* Theoretically, we could one day use 2.4 helpers, but for now it
just confuses depmod --RR */
EXPORT_NO_SYMBOLS;
static struct firewall_ops *fwops;
/* From ip_fw_compat_redir.c */
extern unsigned int
do_redirect(struct sk_buff *skb,
const struct net_device *dev,
u_int16_t redirpt);
extern void
check_for_redirect(struct sk_buff *skb);
extern void
check_for_unredirect(struct sk_buff *skb);
/* From ip_fw_compat_masq.c */
extern unsigned int
do_masquerade(struct sk_buff **pskb, const struct net_device *dev);
extern unsigned int
check_for_masq_error(struct sk_buff *pskb);
extern unsigned int
check_for_demasq(struct sk_buff **pskb);
extern int __init masq_init(void);
extern void masq_cleanup(void);
/* They call these; we do what they want. */
int register_firewall(int pf, struct firewall_ops *fw)
{
if (pf != PF_INET) {
printk("Attempt to register non-IP firewall module.\n");
return -EINVAL;
}
if (fwops) {
printk("Attempt to register multiple firewall modules.\n");
return -EBUSY;
}
fwops = fw;
return 0;
}
int unregister_firewall(int pf, struct firewall_ops *fw)
{
fwops = NULL;
return 0;
}
static unsigned int
fw_in(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
int ret = FW_BLOCK;
u_int16_t redirpt;
/* Assume worse case: any hook could change packet */
(*pskb)->nfcache |= NFC_UNKNOWN | NFC_ALTERED;
if ((*pskb)->ip_summed == CHECKSUM_HW)
(*pskb)->ip_summed = CHECKSUM_NONE;
switch (hooknum) {
case NF_IP_PRE_ROUTING:
if (fwops->fw_acct_in)
fwops->fw_acct_in(fwops, PF_INET,
(struct net_device *)in,
(*pskb)->nh.raw, &redirpt, pskb);
if ((*pskb)->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
*pskb = ip_ct_gather_frags(*pskb);
if (!*pskb)
return NF_STOLEN;
}
ret = fwops->fw_input(fwops, PF_INET, (struct net_device *)in,
(*pskb)->nh.raw, &redirpt, pskb);
break;
case NF_IP_FORWARD:
/* Connection will only be set if it was
demasqueraded: if so, skip forward chain. */
if ((*pskb)->nfct)
ret = FW_ACCEPT;
else ret = fwops->fw_forward(fwops, PF_INET,
(struct net_device *)out,
(*pskb)->nh.raw, &redirpt, pskb);
break;
case NF_IP_POST_ROUTING:
ret = fwops->fw_output(fwops, PF_INET,
(struct net_device *)out,
(*pskb)->nh.raw, &redirpt, pskb);
if (ret == FW_ACCEPT || ret == FW_SKIP) {
if (fwops->fw_acct_out)
fwops->fw_acct_out(fwops, PF_INET,
(struct net_device *)out,
(*pskb)->nh.raw, &redirpt,
pskb);
/* ip_conntrack_confirm return NF_DROP or NF_ACCEPT */
if (ip_conntrack_confirm(*pskb) == NF_DROP)
ret = FW_BLOCK;
}
break;
}
switch (ret) {
case FW_REJECT: {
/* Alexey says:
*
* Generally, routing is THE FIRST thing to make, when
* packet enters IP stack. Before packet is routed you
* cannot call any service routines from IP stack. */
struct iphdr *iph = (*pskb)->nh.iph;
if ((*pskb)->dst != NULL
|| ip_route_input(*pskb, iph->daddr, iph->saddr, iph->tos,
(struct net_device *)in) == 0)
icmp_send(*pskb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH,
0);
return NF_DROP;
}
case FW_ACCEPT:
case FW_SKIP:
if (hooknum == NF_IP_PRE_ROUTING) {
check_for_demasq(pskb);
check_for_redirect(*pskb);
} else if (hooknum == NF_IP_POST_ROUTING) {
check_for_unredirect(*pskb);
/* Handle ICMP errors from client here */
if ((*pskb)->nh.iph->protocol == IPPROTO_ICMP
&& (*pskb)->nfct)
check_for_masq_error(*pskb);
}
return NF_ACCEPT;
case FW_MASQUERADE:
if (hooknum == NF_IP_FORWARD)
return do_masquerade(pskb, out);
else return NF_ACCEPT;
case FW_REDIRECT:
if (hooknum == NF_IP_PRE_ROUTING)
return do_redirect(*pskb, in, redirpt);
else return NF_ACCEPT;
default:
/* FW_BLOCK */
return NF_DROP;
}
}
static unsigned int fw_confirm(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
return ip_conntrack_confirm(*pskb);
}
extern int ip_fw_ctl(int optval, void *m, unsigned int len);
static int sock_fn(struct sock *sk, int optval, void *user, unsigned int len)
{
/* MAX of:
2.2: sizeof(struct ip_fwtest) (~14x4 + 3x4 = 17x4)
2.2: sizeof(struct ip_fwnew) (~1x4 + 15x4 + 3x4 + 3x4 = 22x4)
2.0: sizeof(struct ip_fw) (~25x4)
We can't include both 2.0 and 2.2 headers, they conflict.
Hence, 200 is a good number. --RR */
char tmp_fw[200];
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (len > sizeof(tmp_fw) || len < 1)
return -EINVAL;
if (copy_from_user(&tmp_fw, user, len))
return -EFAULT;
return -ip_fw_ctl(optval, &tmp_fw, len);
}
static struct nf_hook_ops preroute_ops
= { { NULL, NULL }, fw_in, PF_INET, NF_IP_PRE_ROUTING, NF_IP_PRI_FILTER };
static struct nf_hook_ops postroute_ops
= { { NULL, NULL }, fw_in, PF_INET, NF_IP_POST_ROUTING, NF_IP_PRI_FILTER };
static struct nf_hook_ops forward_ops
= { { NULL, NULL }, fw_in, PF_INET, NF_IP_FORWARD, NF_IP_PRI_FILTER };
static struct nf_hook_ops local_in_ops
= { { NULL, NULL }, fw_confirm, PF_INET, NF_IP_LOCAL_IN, NF_IP_PRI_LAST - 1 };
static struct nf_sockopt_ops sock_ops
= { { NULL, NULL }, PF_INET, 64, 64 + 1024 + 1, &sock_fn, 0, 0, NULL,
0, NULL };
extern int ipfw_init_or_cleanup(int init);
static int init_or_cleanup(int init)
{
int ret = 0;
if (!init) goto cleanup;
ret = nf_register_sockopt(&sock_ops);
if (ret < 0)
goto cleanup_nothing;
ret = ipfw_init_or_cleanup(1);
if (ret < 0)
goto cleanup_sockopt;
ret = masq_init();
if (ret < 0)
goto cleanup_ipfw;
nf_register_hook(&preroute_ops);
nf_register_hook(&postroute_ops);
nf_register_hook(&forward_ops);
nf_register_hook(&local_in_ops);
return ret;
cleanup:
nf_unregister_hook(&preroute_ops);
nf_unregister_hook(&postroute_ops);
nf_unregister_hook(&forward_ops);
nf_unregister_hook(&local_in_ops);
masq_cleanup();
cleanup_ipfw:
ipfw_init_or_cleanup(0);
cleanup_sockopt:
nf_unregister_sockopt(&sock_ops);
cleanup_nothing:
return ret;
}
static int __init init(void)
{
return init_or_cleanup(1);
}
static void __exit fini(void)
{
init_or_cleanup(0);
}
module_init(init);
module_exit(fini);
|