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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [net/] [ipv4/] [netfilter.c] - Blame information for rev 17

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Line No. Rev Author Line
1 3 xianfeng 
/* IPv4 specific functions of netfilter core */
2 
#include <linux/kernel.h>
3 
#include <linux/netfilter.h>
4 
#include <linux/netfilter_ipv4.h>
5 
#include <linux/ip.h>
6 
#include <linux/skbuff.h>
7 
#include <net/route.h>
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#include <net/xfrm.h>
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#include <net/ip.h>
10 
 
11 
/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
12 
int ip_route_me_harder(struct sk_buff *skb, unsigned addr_type)
13 
{
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        const struct iphdr *iph = ip_hdr(skb);
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        struct rtable *rt;
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        struct flowi fl = {};
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        struct dst_entry *odst;
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        unsigned int hh_len;
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        unsigned int type;
20 
 
21 
        type = inet_addr_type(iph->saddr);
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        if (addr_type == RTN_UNSPEC)
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                addr_type = type;
24 
 
25 
        /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
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         * packets with foreign saddr to appear on the NF_IP_LOCAL_OUT hook.
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         */
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        if (addr_type == RTN_LOCAL) {
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                fl.nl_u.ip4_u.daddr = iph->daddr;
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                if (type == RTN_LOCAL)
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                        fl.nl_u.ip4_u.saddr = iph->saddr;
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                fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
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                fl.oif = skb->sk ? skb->sk->sk_bound_dev_if : 0;
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                fl.mark = skb->mark;
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                if (ip_route_output_key(&rt, &fl) != 0)
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                        return -1;
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                /* Drop old route. */
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                dst_release(skb->dst);
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                skb->dst = &rt->u.dst;
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        } else {
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                /* non-local src, find valid iif to satisfy
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                 * rp-filter when calling ip_route_input. */
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                fl.nl_u.ip4_u.daddr = iph->saddr;
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                if (ip_route_output_key(&rt, &fl) != 0)
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                        return -1;
47 
 
48 
                odst = skb->dst;
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                if (ip_route_input(skb, iph->daddr, iph->saddr,
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                                   RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
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                        dst_release(&rt->u.dst);
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                        return -1;
53 
                }
54 
                dst_release(&rt->u.dst);
55 
                dst_release(odst);
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        }
57 
 
58 
        if (skb->dst->error)
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                return -1;
60 
 
61 
#ifdef CONFIG_XFRM
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        if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
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            xfrm_decode_session(skb, &fl, AF_INET) == 0)
64 
                if (xfrm_lookup(&skb->dst, &fl, skb->sk, 0))
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                        return -1;
66 
#endif
67 
 
68 
        /* Change in oif may mean change in hh_len. */
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        hh_len = skb->dst->dev->hard_header_len;
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        if (skb_headroom(skb) < hh_len &&
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            pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC))
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                return -1;
73 
 
74 
        return 0;
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}
76 
EXPORT_SYMBOL(ip_route_me_harder);
77 
 
78 
#ifdef CONFIG_XFRM
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int ip_xfrm_me_harder(struct sk_buff *skb)
80 
{
81 
        struct flowi fl;
82 
        unsigned int hh_len;
83 
        struct dst_entry *dst;
84 
 
85 
        if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED)
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                return 0;
87 
        if (xfrm_decode_session(skb, &fl, AF_INET) < 0)
88 
                return -1;
89 
 
90 
        dst = skb->dst;
91 
        if (dst->xfrm)
92 
                dst = ((struct xfrm_dst *)dst)->route;
93 
        dst_hold(dst);
94 
 
95 
        if (xfrm_lookup(&dst, &fl, skb->sk, 0) < 0)
96 
                return -1;
97 
 
98 
        dst_release(skb->dst);
99 
        skb->dst = dst;
100 
 
101 
        /* Change in oif may mean change in hh_len. */
102 
        hh_len = skb->dst->dev->hard_header_len;
103 
        if (skb_headroom(skb) < hh_len &&
104 
            pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC))
105 
                return -1;
106 
        return 0;
107 
}
108 
EXPORT_SYMBOL(ip_xfrm_me_harder);
109 
#endif
110 
 
111 
void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
112 
EXPORT_SYMBOL(ip_nat_decode_session);
113 
 
114 
/*
115 
 * Extra routing may needed on local out, as the QUEUE target never
116 
 * returns control to the table.
117 
 */
118 
 
119 
struct ip_rt_info {
120 
        __be32 daddr;
121 
        __be32 saddr;
122 
        u_int8_t tos;
123 
};
124 
 
125 
static void nf_ip_saveroute(const struct sk_buff *skb, struct nf_info *info)
126 
{
127 
        struct ip_rt_info *rt_info = nf_info_reroute(info);
128 
 
129 
        if (info->hook == NF_IP_LOCAL_OUT) {
130 
                const struct iphdr *iph = ip_hdr(skb);
131 
 
132 
                rt_info->tos = iph->tos;
133 
                rt_info->daddr = iph->daddr;
134 
                rt_info->saddr = iph->saddr;
135 
        }
136 
}
137 
 
138 
static int nf_ip_reroute(struct sk_buff *skb, const struct nf_info *info)
139 
{
140 
        const struct ip_rt_info *rt_info = nf_info_reroute(info);
141 
 
142 
        if (info->hook == NF_IP_LOCAL_OUT) {
143 
                const struct iphdr *iph = ip_hdr(skb);
144 
 
145 
                if (!(iph->tos == rt_info->tos
146 
                      && iph->daddr == rt_info->daddr
147 
                      && iph->saddr == rt_info->saddr))
148 
                        return ip_route_me_harder(skb, RTN_UNSPEC);
149 
        }
150 
        return 0;
151 
}
152 
 
153 
__sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
154 
                            unsigned int dataoff, u_int8_t protocol)
155 
{
156 
        const struct iphdr *iph = ip_hdr(skb);
157 
        __sum16 csum = 0;
158 
 
159 
        switch (skb->ip_summed) {
160 
        case CHECKSUM_COMPLETE:
161 
                if (hook != NF_IP_PRE_ROUTING && hook != NF_IP_LOCAL_IN)
162 
                        break;
163 
                if ((protocol == 0 && !csum_fold(skb->csum)) ||
164 
                    !csum_tcpudp_magic(iph->saddr, iph->daddr,
165 
                                       skb->len - dataoff, protocol,
166 
                                       skb->csum)) {
167 
                        skb->ip_summed = CHECKSUM_UNNECESSARY;
168 
                        break;
169 
                }
170 
                /* fall through */
171 
        case CHECKSUM_NONE:
172 
                if (protocol == 0)
173 
                        skb->csum = 0;
174 
                else
175 
                        skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
176 
                                                       skb->len - dataoff,
177 
                                                       protocol, 0);
178 
                csum = __skb_checksum_complete(skb);
179 
        }
180 
        return csum;
181 
}
182 
 
183 
EXPORT_SYMBOL(nf_ip_checksum);
184 
 
185 
static struct nf_afinfo nf_ip_afinfo = {
186 
        .family         = AF_INET,
187 
        .checksum       = nf_ip_checksum,
188 
        .saveroute      = nf_ip_saveroute,
189 
        .reroute        = nf_ip_reroute,
190 
        .route_key_size = sizeof(struct ip_rt_info),
191 
};
192 
 
193 
static int ipv4_netfilter_init(void)
194 
{
195 
        return nf_register_afinfo(&nf_ip_afinfo);
196 
}
197 
 
198 
static void ipv4_netfilter_fini(void)
199 
{
200 
        nf_unregister_afinfo(&nf_ip_afinfo);
201 
}
202 
 
203 
module_init(ipv4_netfilter_init);
204 
module_exit(ipv4_netfilter_fini);

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