diff options
Diffstat (limited to 'br-nf-bds/linux2.5/net/ipv4/netfilter/ip_tables.c')
| -rw-r--r-- | br-nf-bds/linux2.5/net/ipv4/netfilter/ip_tables.c | 1811 |
1 files changed, 1811 insertions, 0 deletions
diff --git a/br-nf-bds/linux2.5/net/ipv4/netfilter/ip_tables.c b/br-nf-bds/linux2.5/net/ipv4/netfilter/ip_tables.c new file mode 100644 index 0000000..928e67a --- /dev/null +++ b/br-nf-bds/linux2.5/net/ipv4/netfilter/ip_tables.c @@ -0,0 +1,1811 @@ +/* + * Packet matching code. + * + * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling + * Copyright (C) 2009-2002 Netfilter core team <coreteam@netfilter.org> + * + * 19 Jan 2002 Harald Welte <laforge@gnumonks.org> + * - increase module usage count as soon as we have rules inside + * a table + */ +#include <linux/config.h> +#include <linux/cache.h> +#include <linux/skbuff.h> +#include <linux/kmod.h> +#include <linux/vmalloc.h> +#include <linux/netdevice.h> +#include <linux/module.h> +#include <linux/tcp.h> +#include <linux/udp.h> +#include <linux/icmp.h> +#include <net/ip.h> +#include <asm/uaccess.h> +#include <asm/semaphore.h> +#include <linux/proc_fs.h> + +#include <linux/netfilter_ipv4/ip_tables.h> + +/*#define DEBUG_IP_FIREWALL*/ +/*#define DEBUG_ALLOW_ALL*/ /* Useful for remote debugging */ +/*#define DEBUG_IP_FIREWALL_USER*/ + +#ifdef DEBUG_IP_FIREWALL +#define dprintf(format, args...) printk(format , ## args) +#else +#define dprintf(format, args...) +#endif + +#ifdef DEBUG_IP_FIREWALL_USER +#define duprintf(format, args...) printk(format , ## args) +#else +#define duprintf(format, args...) +#endif + +#ifdef CONFIG_NETFILTER_DEBUG +#define IP_NF_ASSERT(x) \ +do { \ + if (!(x)) \ + printk("IP_NF_ASSERT: %s:%s:%u\n", \ + __FUNCTION__, __FILE__, __LINE__); \ +} while(0) +#else +#define IP_NF_ASSERT(x) +#endif +#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1)) + +/* Mutex protects lists (only traversed in user context). */ +static DECLARE_MUTEX(ipt_mutex); + +/* Must have mutex */ +#define ASSERT_READ_LOCK(x) IP_NF_ASSERT(down_trylock(&ipt_mutex) != 0) +#define ASSERT_WRITE_LOCK(x) IP_NF_ASSERT(down_trylock(&ipt_mutex) != 0) +#include <linux/netfilter_ipv4/lockhelp.h> +#include <linux/netfilter_ipv4/listhelp.h> + +#if 0 +/* All the better to debug you with... */ +#define static +#define inline +#endif + +/* Locking is simple: we assume at worst case there will be one packet + in user context and one from bottom halves (or soft irq if Alexey's + softnet patch was applied). + + We keep a set of rules for each CPU, so we can avoid write-locking + them; doing a readlock_bh() stops packets coming through if we're + in user context. + + To be cache friendly on SMP, we arrange them like so: + [ n-entries ] + ... cache-align padding ... + [ n-entries ] + + Hence the start of any table is given by get_table() below. */ + +/* The table itself */ +struct ipt_table_info +{ + /* Size per table */ + unsigned int size; + /* Number of entries: FIXME. --RR */ + unsigned int number; + /* Initial number of entries. Needed for module usage count */ + unsigned int initial_entries; + + /* Entry points and underflows */ + unsigned int hook_entry[NF_IP_NUMHOOKS]; + unsigned int underflow[NF_IP_NUMHOOKS]; + + /* ipt_entry tables: one per CPU */ + char entries[0] ____cacheline_aligned; +}; + +static LIST_HEAD(ipt_target); +static LIST_HEAD(ipt_match); +static LIST_HEAD(ipt_tables); +#define ADD_COUNTER(c,b,p) do { (c).bcnt += (b); (c).pcnt += (p); } while(0) + +#ifdef CONFIG_SMP +#define TABLE_OFFSET(t,p) (SMP_ALIGN((t)->size)*(p)) +#else +#define TABLE_OFFSET(t,p) 0 +#endif + +#if 0 +#define down(x) do { printk("DOWN:%u:" #x "\n", __LINE__); down(x); } while(0) +#define down_interruptible(x) ({ int __r; printk("DOWNi:%u:" #x "\n", __LINE__); __r = down_interruptible(x); if (__r != 0) printk("ABORT-DOWNi:%u\n", __LINE__); __r; }) +#define up(x) do { printk("UP:%u:" #x "\n", __LINE__); up(x); } while(0) +#endif + +/* Returns whether matches rule or not. */ +static inline int +ip_packet_match(const struct iphdr *ip, + const char *indev, + const char *physindev, + const char *outdev, + const char *physoutdev, + const struct ipt_ip *ipinfo, + int isfrag) +{ + size_t i; + unsigned long ret; + unsigned long ret2; + +#define FWINV(bool,invflg) ((bool) ^ !!(ipinfo->invflags & invflg)) + + if (FWINV((ip->saddr&ipinfo->smsk.s_addr) != ipinfo->src.s_addr, + IPT_INV_SRCIP) + || FWINV((ip->daddr&ipinfo->dmsk.s_addr) != ipinfo->dst.s_addr, + IPT_INV_DSTIP)) { + dprintf("Source or dest mismatch.\n"); + + dprintf("SRC: %u.%u.%u.%u. Mask: %u.%u.%u.%u. Target: %u.%u.%u.%u.%s\n", + NIPQUAD(ip->saddr), + NIPQUAD(ipinfo->smsk.s_addr), + NIPQUAD(ipinfo->src.s_addr), + ipinfo->invflags & IPT_INV_SRCIP ? " (INV)" : ""); + dprintf("DST: %u.%u.%u.%u Mask: %u.%u.%u.%u Target: %u.%u.%u.%u.%s\n", + NIPQUAD(ip->daddr), + NIPQUAD(ipinfo->dmsk.s_addr), + NIPQUAD(ipinfo->dst.s_addr), + ipinfo->invflags & IPT_INV_DSTIP ? " (INV)" : ""); + return 0; + } + + /* Look for ifname matches; this should unroll nicely. */ + for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) { + ret |= (((const unsigned long *)indev)[i] + ^ ((const unsigned long *)ipinfo->iniface)[i]) + & ((const unsigned long *)ipinfo->iniface_mask)[i]; + } + + for (i = 0, ret2 = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) { + ret2 |= (((const unsigned long *)physindev)[i] + ^ ((const unsigned long *)ipinfo->iniface)[i]) + & ((const unsigned long *)ipinfo->iniface_mask)[i]; + } + + if (FWINV(ret != 0 && ret2 != 0, IPT_INV_VIA_IN)) { + dprintf("VIA in mismatch (%s vs %s).%s\n", + indev, ipinfo->iniface, + ipinfo->invflags&IPT_INV_VIA_IN ?" (INV)":""); + return 0; + } + + for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) { + ret |= (((const unsigned long *)outdev)[i] + ^ ((const unsigned long *)ipinfo->outiface)[i]) + & ((const unsigned long *)ipinfo->outiface_mask)[i]; + } + + for (i = 0, ret2 = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) { + ret2 |= (((const unsigned long *)physoutdev)[i] + ^ ((const unsigned long *)ipinfo->outiface)[i]) + & ((const unsigned long *)ipinfo->outiface_mask)[i]; + } + + if (FWINV(ret != 0 && ret2 != 0, IPT_INV_VIA_OUT)) { + dprintf("VIA out mismatch (%s vs %s).%s\n", + outdev, ipinfo->outiface, + ipinfo->invflags&IPT_INV_VIA_OUT ?" (INV)":""); + return 0; + } + + /* Check specific protocol */ + if (ipinfo->proto + && FWINV(ip->protocol != ipinfo->proto, IPT_INV_PROTO)) { + dprintf("Packet protocol %hi does not match %hi.%s\n", + ip->protocol, ipinfo->proto, + ipinfo->invflags&IPT_INV_PROTO ? " (INV)":""); + return 0; + } + + /* If we have a fragment rule but the packet is not a fragment + * then we return zero */ + if (FWINV((ipinfo->flags&IPT_F_FRAG) && !isfrag, IPT_INV_FRAG)) { + dprintf("Fragment rule but not fragment.%s\n", + ipinfo->invflags & IPT_INV_FRAG ? " (INV)" : ""); + return 0; + } + + return 1; +} + +static inline int +ip_checkentry(const struct ipt_ip *ip) +{ + if (ip->flags & ~IPT_F_MASK) { + duprintf("Unknown flag bits set: %08X\n", + ip->flags & ~IPT_F_MASK); + return 0; + } + if (ip->invflags & ~IPT_INV_MASK) { + duprintf("Unknown invflag bits set: %08X\n", + ip->invflags & ~IPT_INV_MASK); + return 0; + } + return 1; +} + +static unsigned int +ipt_error(struct sk_buff **pskb, + unsigned int hooknum, + const struct net_device *in, + const struct net_device *out, + const void *targinfo, + void *userinfo) +{ + if (net_ratelimit()) + printk("ip_tables: error: `%s'\n", (char *)targinfo); + + return NF_DROP; +} + +static inline +int do_match(struct ipt_entry_match *m, + const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + int offset, + const void *hdr, + u_int16_t datalen, + int *hotdrop) +{ + /* Stop iteration if it doesn't match */ + if (!m->u.kernel.match->match(skb, in, out, m->data, + offset, hdr, datalen, hotdrop)) + return 1; + else + return 0; +} + +static inline struct ipt_entry * +get_entry(void *base, unsigned int offset) +{ + return (struct ipt_entry *)(base + offset); +} + +/* Returns one of the generic firewall policies, like NF_ACCEPT. */ +unsigned int +ipt_do_table(struct sk_buff **pskb, + unsigned int hook, + const struct net_device *in, + const struct net_device *out, + struct ipt_table *table, + void *userdata) +{ + static const char nulldevname[IFNAMSIZ] = { 0 }; + u_int16_t offset; + struct iphdr *ip; + void *protohdr; + u_int16_t datalen; + int hotdrop = 0; + /* Initializing verdict to NF_DROP keeps gcc happy. */ + unsigned int verdict = NF_DROP; + const char *indev, *outdev; + const char *physindev, *physoutdev; + void *table_base; + struct ipt_entry *e, *back; + + /* Initialization */ + ip = (*pskb)->nh.iph; + protohdr = (u_int32_t *)ip + ip->ihl; + datalen = (*pskb)->len - ip->ihl * 4; + indev = in ? in->name : nulldevname; + outdev = out ? out->name : nulldevname; + physindev = (*pskb)->physindev ? (*pskb)->physindev->name : nulldevname; + physoutdev = (*pskb)->physoutdev ? (*pskb)->physoutdev->name : nulldevname; + + /* We handle fragments by dealing with the first fragment as + * if it was a normal packet. All other fragments are treated + * normally, except that they will NEVER match rules that ask + * things we don't know, ie. tcp syn flag or ports). If the + * rule is also a fragment-specific rule, non-fragments won't + * match it. */ + offset = ntohs(ip->frag_off) & IP_OFFSET; + + read_lock_bh(&table->lock); + IP_NF_ASSERT(table->valid_hooks & (1 << hook)); + table_base = (void *)table->private->entries + + TABLE_OFFSET(table->private, smp_processor_id()); + e = get_entry(table_base, table->private->hook_entry[hook]); + +#ifdef CONFIG_NETFILTER_DEBUG + /* Check noone else using our table */ + if (((struct ipt_entry *)table_base)->comefrom != 0xdead57ac + && ((struct ipt_entry *)table_base)->comefrom != 0xeeeeeeec) { + printk("ASSERT: CPU #%u, %s comefrom(%p) = %X\n", + smp_processor_id(), + table->name, + &((struct ipt_entry *)table_base)->comefrom, + ((struct ipt_entry *)table_base)->comefrom); + } + ((struct ipt_entry *)table_base)->comefrom = 0x57acc001; +#endif + + /* For return from builtin chain */ + back = get_entry(table_base, table->private->underflow[hook]); + + do { + IP_NF_ASSERT(e); + IP_NF_ASSERT(back); + (*pskb)->nfcache |= e->nfcache; + if (ip_packet_match(ip, indev, physindev, outdev, physoutdev, &e->ip, offset)) { + struct ipt_entry_target *t; + + if (IPT_MATCH_ITERATE(e, do_match, + *pskb, in, out, + offset, protohdr, + datalen, &hotdrop) != 0) + goto no_match; + + ADD_COUNTER(e->counters, ntohs(ip->tot_len), 1); + + t = ipt_get_target(e); + IP_NF_ASSERT(t->u.kernel.target); + /* Standard target? */ + if (!t->u.kernel.target->target) { + int v; + + v = ((struct ipt_standard_target *)t)->verdict; + if (v < 0) { + /* Pop from stack? */ + if (v != IPT_RETURN) { + verdict = (unsigned)(-v) - 1; + break; + } + e = back; + back = get_entry(table_base, + back->comefrom); + continue; + } + if (table_base + v + != (void *)e + e->next_offset) { + /* Save old back ptr in next entry */ + struct ipt_entry *next + = (void *)e + e->next_offset; + next->comefrom + = (void *)back - table_base; + /* set back pointer to next entry */ + back = next; + } + + e = get_entry(table_base, v); + } else { + /* Targets which reenter must return + abs. verdicts */ +#ifdef CONFIG_NETFILTER_DEBUG + ((struct ipt_entry *)table_base)->comefrom + = 0xeeeeeeec; +#endif + verdict = t->u.kernel.target->target(pskb, + hook, + in, out, + t->data, + userdata); + +#ifdef CONFIG_NETFILTER_DEBUG + if (((struct ipt_entry *)table_base)->comefrom + != 0xeeeeeeec + && verdict == IPT_CONTINUE) { + printk("Target %s reentered!\n", + t->u.kernel.target->name); + verdict = NF_DROP; + } + ((struct ipt_entry *)table_base)->comefrom + = 0x57acc001; +#endif + /* Target might have changed stuff. */ + ip = (*pskb)->nh.iph; + protohdr = (u_int32_t *)ip + ip->ihl; + datalen = (*pskb)->len - ip->ihl * 4; + + if (verdict == IPT_CONTINUE) + e = (void *)e + e->next_offset; + else + /* Verdict */ + break; + } + } else { + + no_match: + e = (void *)e + e->next_offset; + } + } while (!hotdrop); + +#ifdef CONFIG_NETFILTER_DEBUG + ((struct ipt_entry *)table_base)->comefrom = 0xdead57ac; +#endif + read_unlock_bh(&table->lock); + +#ifdef DEBUG_ALLOW_ALL + return NF_ACCEPT; +#else + if (hotdrop) + return NF_DROP; + else return verdict; +#endif +} + +/* If it succeeds, returns element and locks mutex */ +static inline void * +find_inlist_lock_noload(struct list_head *head, + const char *name, + int *error, + struct semaphore *mutex) +{ + void *ret; + +#if 0 + duprintf("find_inlist: searching for `%s' in %s.\n", + name, head == &ipt_target ? "ipt_target" + : head == &ipt_match ? "ipt_match" + : head == &ipt_tables ? "ipt_tables" : "UNKNOWN"); +#endif + + *error = down_interruptible(mutex); + if (*error != 0) + return NULL; + + ret = list_named_find(head, name); + if (!ret) { + *error = -ENOENT; + up(mutex); + } + return ret; +} + +#ifndef CONFIG_KMOD +#define find_inlist_lock(h,n,p,e,m) find_inlist_lock_noload((h),(n),(e),(m)) +#else +static void * +find_inlist_lock(struct list_head *head, + const char *name, + const char *prefix, + int *error, + struct semaphore *mutex) +{ + void *ret; + + ret = find_inlist_lock_noload(head, name, error, mutex); + if (!ret) { + char modulename[IPT_FUNCTION_MAXNAMELEN + strlen(prefix) + 1]; + strcpy(modulename, prefix); + strcat(modulename, name); + duprintf("find_inlist: loading `%s'.\n", modulename); + request_module(modulename); + ret = find_inlist_lock_noload(head, name, error, mutex); + } + + return ret; +} +#endif + +static inline struct ipt_table * +find_table_lock(const char *name, int *error, struct semaphore *mutex) +{ + return find_inlist_lock(&ipt_tables, name, "iptable_", error, mutex); +} + +static inline struct ipt_match * +find_match_lock(const char *name, int *error, struct semaphore *mutex) +{ + return find_inlist_lock(&ipt_match, name, "ipt_", error, mutex); +} + +static inline struct ipt_target * +find_target_lock(const char *name, int *error, struct semaphore *mutex) +{ + return find_inlist_lock(&ipt_target, name, "ipt_", error, mutex); +} + +/* All zeroes == unconditional rule. */ +static inline int +unconditional(const struct ipt_ip *ip) +{ + unsigned int i; + + for (i = 0; i < sizeof(*ip)/sizeof(__u32); i++) + if (((__u32 *)ip)[i]) + return 0; + + return 1; +} + +/* Figures out from what hook each rule can be called: returns 0 if + there are loops. Puts hook bitmask in comefrom. */ +static int +mark_source_chains(struct ipt_table_info *newinfo, unsigned int valid_hooks) +{ + unsigned int hook; + + /* No recursion; use packet counter to save back ptrs (reset + to 0 as we leave), and comefrom to save source hook bitmask */ + for (hook = 0; hook < NF_IP_NUMHOOKS; hook++) { + unsigned int pos = newinfo->hook_entry[hook]; + struct ipt_entry *e + = (struct ipt_entry *)(newinfo->entries + pos); + + if (!(valid_hooks & (1 << hook))) + continue; + + /* Set initial back pointer. */ + e->counters.pcnt = pos; + + for (;;) { + struct ipt_standard_target *t + = (void *)ipt_get_target(e); + + if (e->comefrom & (1 << NF_IP_NUMHOOKS)) { + printk("iptables: loop hook %u pos %u %08X.\n", + hook, pos, e->comefrom); + return 0; + } + e->comefrom + |= ((1 << hook) | (1 << NF_IP_NUMHOOKS)); + + /* Unconditional return/END. */ + if (e->target_offset == sizeof(struct ipt_entry) + && (strcmp(t->target.u.user.name, + IPT_STANDARD_TARGET) == 0) + && t->verdict < 0 + && unconditional(&e->ip)) { + unsigned int oldpos, size; + + /* Return: backtrack through the last + big jump. */ + do { + e->comefrom ^= (1<<NF_IP_NUMHOOKS); +#ifdef DEBUG_IP_FIREWALL_USER + if (e->comefrom + & (1 << NF_IP_NUMHOOKS)) { + duprintf("Back unset " + "on hook %u " + "rule %u\n", + hook, pos); + } +#endif + oldpos = pos; + pos = e->counters.pcnt; + e->counters.pcnt = 0; + + /* We're at the start. */ + if (pos == oldpos) + goto next; + + e = (struct ipt_entry *) + (newinfo->entries + pos); + } while (oldpos == pos + e->next_offset); + + /* Move along one */ + size = e->next_offset; + e = (struct ipt_entry *) + (newinfo->entries + pos + size); + e->counters.pcnt = pos; + pos += size; + } else { + int newpos = t->verdict; + + if (strcmp(t->target.u.user.name, + IPT_STANDARD_TARGET) == 0 + && newpos >= 0) { + /* This a jump; chase it. */ + duprintf("Jump rule %u -> %u\n", + pos, newpos); + } else { + /* ... this is a fallthru */ + newpos = pos + e->next_offset; + } + e = (struct ipt_entry *) + (newinfo->entries + newpos); + e->counters.pcnt = pos; + pos = newpos; + } + } + next: + duprintf("Finished chain %u\n", hook); + } + return 1; +} + +static inline int +cleanup_match(struct ipt_entry_match *m, unsigned int *i) +{ + if (i && (*i)-- == 0) + return 1; + + if (m->u.kernel.match->destroy) + m->u.kernel.match->destroy(m->data, + m->u.match_size - sizeof(*m)); + + if (m->u.kernel.match->me) + __MOD_DEC_USE_COUNT(m->u.kernel.match->me); + + return 0; +} + +static inline int +standard_check(const struct ipt_entry_target *t, + unsigned int max_offset) +{ + struct ipt_standard_target *targ = (void *)t; + + /* Check standard info. */ + if (t->u.target_size + != IPT_ALIGN(sizeof(struct ipt_standard_target))) { + duprintf("standard_check: target size %u != %u\n", + t->u.target_size, + IPT_ALIGN(sizeof(struct ipt_standard_target))); + return 0; + } + + if (targ->verdict >= 0 + && targ->verdict > max_offset - sizeof(struct ipt_entry)) { + duprintf("ipt_standard_check: bad verdict (%i)\n", + targ->verdict); + return 0; + } + + if (targ->verdict < -NF_MAX_VERDICT - 1) { + duprintf("ipt_standard_check: bad negative verdict (%i)\n", + targ->verdict); + return 0; + } + return 1; +} + +static inline int +check_match(struct ipt_entry_match *m, + const char *name, + const struct ipt_ip *ip, + unsigned int hookmask, + unsigned int *i) +{ + int ret; + struct ipt_match *match; + + match = find_match_lock(m->u.user.name, &ret, &ipt_mutex); + if (!match) { + duprintf("check_match: `%s' not found\n", m->u.user.name); + return ret; + } + if (match->me) + __MOD_INC_USE_COUNT(match->me); + m->u.kernel.match = match; + up(&ipt_mutex); + + if (m->u.kernel.match->checkentry + && !m->u.kernel.match->checkentry(name, ip, m->data, + m->u.match_size - sizeof(*m), + hookmask)) { + if (m->u.kernel.match->me) + __MOD_DEC_USE_COUNT(m->u.kernel.match->me); + duprintf("ip_tables: check failed for `%s'.\n", + m->u.kernel.match->name); + return -EINVAL; + } + + (*i)++; + return 0; +} + +static struct ipt_target ipt_standard_target; + +static inline int +check_entry(struct ipt_entry *e, const char *name, unsigned int size, + unsigned int *i) +{ + struct ipt_entry_target *t; + struct ipt_target *target; + int ret; + unsigned int j; + + if (!ip_checkentry(&e->ip)) { + duprintf("ip_tables: ip check failed %p %s.\n", e, name); + return -EINVAL; + } + + j = 0; + ret = IPT_MATCH_ITERATE(e, check_match, name, &e->ip, e->comefrom, &j); + if (ret != 0) + goto cleanup_matches; + + t = ipt_get_target(e); + target = find_target_lock(t->u.user.name, &ret, &ipt_mutex); + if (!target) { + duprintf("check_entry: `%s' not found\n", t->u.user.name); + goto cleanup_matches; + } + if (target->me) + __MOD_INC_USE_COUNT(target->me); + t->u.kernel.target = target; + up(&ipt_mutex); + + if (t->u.kernel.target == &ipt_standard_target) { + if (!standard_check(t, size)) { + ret = -EINVAL; + goto cleanup_matches; + } + } else if (t->u.kernel.target->checkentry + && !t->u.kernel.target->checkentry(name, e, t->data, + t->u.target_size + - sizeof(*t), + e->comefrom)) { + if (t->u.kernel.target->me) + __MOD_DEC_USE_COUNT(t->u.kernel.target->me); + duprintf("ip_tables: check failed for `%s'.\n", + t->u.kernel.target->name); + ret = -EINVAL; + goto cleanup_matches; + } + + (*i)++; + return 0; + + cleanup_matches: + IPT_MATCH_ITERATE(e, cleanup_match, &j); + return ret; +} + +static inline int +check_entry_size_and_hooks(struct ipt_entry *e, + struct ipt_table_info *newinfo, + unsigned char *base, + unsigned char *limit, + const unsigned int *hook_entries, + const unsigned int *underflows, + unsigned int *i) +{ + unsigned int h; + + if ((unsigned long)e % __alignof__(struct ipt_entry) != 0 + || (unsigned char *)e + sizeof(struct ipt_entry) >= limit) { + duprintf("Bad offset %p\n", e); + return -EINVAL; + } + + if (e->next_offset + < sizeof(struct ipt_entry) + sizeof(struct ipt_entry_target)) { + duprintf("checking: element %p size %u\n", + e, e->next_offset); + return -EINVAL; + } + + /* Check hooks & underflows */ + for (h = 0; h < NF_IP_NUMHOOKS; h++) { + if ((unsigned char *)e - base == hook_entries[h]) + newinfo->hook_entry[h] = hook_entries[h]; + if ((unsigned char *)e - base == underflows[h]) + newinfo->underflow[h] = underflows[h]; + } + + /* FIXME: underflows must be unconditional, standard verdicts + < 0 (not IPT_RETURN). --RR */ + + /* Clear counters and comefrom */ + e->counters = ((struct ipt_counters) { 0, 0 }); + e->comefrom = 0; + + (*i)++; + return 0; +} + +static inline int +cleanup_entry(struct ipt_entry *e, unsigned int *i) +{ + struct ipt_entry_target *t; + + if (i && (*i)-- == 0) + return 1; + + /* Cleanup all matches */ + IPT_MATCH_ITERATE(e, cleanup_match, NULL); + t = ipt_get_target(e); + if (t->u.kernel.target->destroy) + t->u.kernel.target->destroy(t->data, + t->u.target_size - sizeof(*t)); + if (t->u.kernel.target->me) + __MOD_DEC_USE_COUNT(t->u.kernel.target->me); + + return 0; +} + +/* Checks and translates the user-supplied table segment (held in + newinfo) */ +static int +translate_table(const char *name, + unsigned int valid_hooks, + struct ipt_table_info *newinfo, + unsigned int size, + unsigned int number, + const unsigned int *hook_entries, + const unsigned int *underflows) +{ + unsigned int i; + int ret; + + newinfo->size = size; + newinfo->number = number; + + /* Init all hooks to impossible value. */ + for (i = 0; i < NF_IP_NUMHOOKS; i++) { + newinfo->hook_entry[i] = 0xFFFFFFFF; + newinfo->underflow[i] = 0xFFFFFFFF; + } + + duprintf("translate_table: size %u\n", newinfo->size); + i = 0; + /* Walk through entries, checking offsets. */ + ret = IPT_ENTRY_ITERATE(newinfo->entries, newinfo->size, + check_entry_size_and_hooks, + newinfo, + newinfo->entries, + newinfo->entries + size, + hook_entries, underflows, &i); + if (ret != 0) + return ret; + + if (i != number) { + duprintf("translate_table: %u not %u entries\n", + i, number); + return -EINVAL; + } + + /* Check hooks all assigned */ + for (i = 0; i < NF_IP_NUMHOOKS; i++) { + /* Only hooks which are valid */ + if (!(valid_hooks & (1 << i))) + continue; + if (newinfo->hook_entry[i] == 0xFFFFFFFF) { + duprintf("Invalid hook entry %u %u\n", + i, hook_entries[i]); + return -EINVAL; + } + if (newinfo->underflow[i] == 0xFFFFFFFF) { + duprintf("Invalid underflow %u %u\n", + i, underflows[i]); + return -EINVAL; + } + } + + if (!mark_source_chains(newinfo, valid_hooks)) + return -ELOOP; + + /* Finally, each sanity check must pass */ + i = 0; + ret = IPT_ENTRY_ITERATE(newinfo->entries, newinfo->size, + check_entry, name, size, &i); + + if (ret != 0) { + IPT_ENTRY_ITERATE(newinfo->entries, newinfo->size, + cleanup_entry, &i); + return ret; + } + + /* And one copy for every other CPU */ + for (i = 1; i < NR_CPUS; i++) { + memcpy(newinfo->entries + SMP_ALIGN(newinfo->size)*i, + newinfo->entries, + SMP_ALIGN(newinfo->size)); + } + + return ret; +} + +static struct ipt_table_info * +replace_table(struct ipt_table *table, + unsigned int num_counters, + struct ipt_table_info *newinfo, + int *error) +{ + struct ipt_table_info *oldinfo; + +#ifdef CONFIG_NETFILTER_DEBUG + { + struct ipt_entry *table_base; + unsigned int i; + + for (i = 0; i < NR_CPUS; i++) { + table_base = + (void *)newinfo->entries + + TABLE_OFFSET(newinfo, i); + + table_base->comefrom = 0xdead57ac; + } + } +#endif + + /* Do the substitution. */ + write_lock_bh(&table->lock); + /* Check inside lock: is the old number correct? */ + if (num_counters != table->private->number) { + duprintf("num_counters != table->private->number (%u/%u)\n", + num_counters, table->private->number); + write_unlock_bh(&table->lock); + *error = -EAGAIN; + return NULL; + } + oldinfo = table->private; + table->private = newinfo; + newinfo->initial_entries = oldinfo->initial_entries; + write_unlock_bh(&table->lock); + + return oldinfo; +} + +/* Gets counters. */ +static inline int +add_entry_to_counter(const struct ipt_entry *e, + struct ipt_counters total[], + unsigned int *i) +{ + ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt); + + (*i)++; + return 0; +} + +static void +get_counters(const struct ipt_table_info *t, + struct ipt_counters counters[]) +{ + unsigned int cpu; + unsigned int i; + + for (cpu = 0; cpu < NR_CPUS; cpu++) { + i = 0; + IPT_ENTRY_ITERATE(t->entries + TABLE_OFFSET(t, cpu), + t->size, + add_entry_to_counter, + counters, + &i); + } +} + +static int +copy_entries_to_user(unsigned int total_size, + struct ipt_table *table, + void *userptr) +{ + unsigned int off, num, countersize; + struct ipt_entry *e; + struct ipt_counters *counters; + int ret = 0; + + /* We need atomic snapshot of counters: rest doesn't change + (other than comefrom, which userspace doesn't care + about). */ + countersize = sizeof(struct ipt_counters) * table->private->number; + counters = vmalloc(countersize); + + if (counters == NULL) + return -ENOMEM; + + /* First, sum counters... */ + memset(counters, 0, countersize); + write_lock_bh(&table->lock); + get_counters(table->private, counters); + write_unlock_bh(&table->lock); + + /* ... then copy entire thing from CPU 0... */ + if (copy_to_user(userptr, table->private->entries, total_size) != 0) { + ret = -EFAULT; + goto free_counters; + } + + /* FIXME: use iterator macros --RR */ + /* ... then go back and fix counters and names */ + for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){ + unsigned int i; + struct ipt_entry_match *m; + struct ipt_entry_target *t; + + e = (struct ipt_entry *)(table->private->entries + off); + if (copy_to_user(userptr + off + + offsetof(struct ipt_entry, counters), + &counters[num], + sizeof(counters[num])) != 0) { + ret = -EFAULT; + goto free_counters; + } + + for (i = sizeof(struct ipt_entry); + i < e->target_offset; + i += m->u.match_size) { + m = (void *)e + i; + + if (copy_to_user(userptr + off + i + + offsetof(struct ipt_entry_match, + u.user.name), + m->u.kernel.match->name, + strlen(m->u.kernel.match->name)+1) + != 0) { + ret = -EFAULT; + goto free_counters; + } + } + + t = ipt_get_target(e); + if (copy_to_user(userptr + off + e->target_offset + + offsetof(struct ipt_entry_target, + u.user.name), + t->u.kernel.target->name, + strlen(t->u.kernel.target->name)+1) != 0) { + ret = -EFAULT; + goto free_counters; + } + } + + free_counters: + vfree(counters); + return ret; +} + +static int +get_entries(const struct ipt_get_entries *entries, + struct ipt_get_entries *uptr) +{ + int ret; + struct ipt_table *t; + + t = find_table_lock(entries->name, &ret, &ipt_mutex); + if (t) { + duprintf("t->private->number = %u\n", + t->private->number); + if (entries->size == t->private->size) + ret = copy_entries_to_user(t->private->size, + t, uptr->entrytable); + else { + duprintf("get_entries: I've got %u not %u!\n", + t->private->size, + entries->size); + ret = -EINVAL; + } + up(&ipt_mutex); + } else + duprintf("get_entries: Can't find %s!\n", + entries->name); + + return ret; +} + +static int +do_replace(void *user, unsigned int len) +{ + int ret; + struct ipt_replace tmp; + struct ipt_table *t; + struct ipt_table_info *newinfo, *oldinfo; + struct ipt_counters *counters; + + if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) + return -EFAULT; + + /* Hack: Causes ipchains to give correct error msg --RR */ + if (len != sizeof(tmp) + tmp.size) + return -ENOPROTOOPT; + + /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */ + if ((SMP_ALIGN(tmp.size) >> PAGE_SHIFT) + 2 > num_physpages) + return -ENOMEM; + + newinfo = vmalloc(sizeof(struct ipt_table_info) + + SMP_ALIGN(tmp.size) * NR_CPUS); + if (!newinfo) + return -ENOMEM; + + if (copy_from_user(newinfo->entries, user + sizeof(tmp), + tmp.size) != 0) { + ret = -EFAULT; + goto free_newinfo; + } + + counters = vmalloc(tmp.num_counters * sizeof(struct ipt_counters)); + if (!counters) { + ret = -ENOMEM; + goto free_newinfo; + } + memset(counters, 0, tmp.num_counters * sizeof(struct ipt_counters)); + + ret = translate_table(tmp.name, tmp.valid_hooks, + newinfo, tmp.size, tmp.num_entries, + tmp.hook_entry, tmp.underflow); + if (ret != 0) + goto free_newinfo_counters; + + duprintf("ip_tables: Translated table\n"); + + t = find_table_lock(tmp.name, &ret, &ipt_mutex); + if (!t) + goto free_newinfo_counters_untrans; + + /* You lied! */ + if (tmp.valid_hooks != t->valid_hooks) { + duprintf("Valid hook crap: %08X vs %08X\n", + tmp.valid_hooks, t->valid_hooks); + ret = -EINVAL; + goto free_newinfo_counters_untrans_unlock; + } + + oldinfo = replace_table(t, tmp.num_counters, newinfo, &ret); + if (!oldinfo) + goto free_newinfo_counters_untrans_unlock; + + /* Update module usage count based on number of rules */ + duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n", + oldinfo->number, oldinfo->initial_entries, newinfo->number); + if (t->me && (oldinfo->number <= oldinfo->initial_entries) && + (newinfo->number > oldinfo->initial_entries)) + __MOD_INC_USE_COUNT(t->me); + else if (t->me && (oldinfo->number > oldinfo->initial_entries) && + (newinfo->number <= oldinfo->initial_entries)) + __MOD_DEC_USE_COUNT(t->me); + + /* Get the old counters. */ + get_counters(oldinfo, counters); + /* Decrease module usage counts and free resource */ + IPT_ENTRY_ITERATE(oldinfo->entries, oldinfo->size, cleanup_entry,NULL); + vfree(oldinfo); + /* Silent error: too late now. */ + copy_to_user(tmp.counters, counters, + sizeof(struct ipt_counters) * tmp.num_counters); + vfree(counters); + up(&ipt_mutex); + return 0; + + free_newinfo_counters_untrans_unlock: + up(&ipt_mutex); + free_newinfo_counters_untrans: + IPT_ENTRY_ITERATE(newinfo->entries, newinfo->size, cleanup_entry,NULL); + free_newinfo_counters: + vfree(counters); + free_newinfo: + vfree(newinfo); + return ret; +} + +/* We're lazy, and add to the first CPU; overflow works its fey magic + * and everything is OK. */ +static inline int +add_counter_to_entry(struct ipt_entry *e, + const struct ipt_counters addme[], + unsigned int *i) +{ +#if 0 + duprintf("add_counter: Entry %u %lu/%lu + %lu/%lu\n", + *i, + (long unsigned int)e->counters.pcnt, + (long unsigned int)e->counters.bcnt, + (long unsigned int)addme[*i].pcnt, + (long unsigned int)addme[*i].bcnt); +#endif + + ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt); + + (*i)++; + return 0; +} + +static int +do_add_counters(void *user, unsigned int len) +{ + unsigned int i; + struct ipt_counters_info tmp, *paddc; + struct ipt_table *t; + int ret; + + if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) + return -EFAULT; + + if (len != sizeof(tmp) + tmp.num_counters*sizeof(struct ipt_counters)) + return -EINVAL; + + paddc = vmalloc(len); + if (!paddc) + return -ENOMEM; + + if (copy_from_user(paddc, user, len) != 0) { + ret = -EFAULT; + goto free; + } + + t = find_table_lock(tmp.name, &ret, &ipt_mutex); + if (!t) + goto free; + + write_lock_bh(&t->lock); + if (t->private->number != paddc->num_counters) { + ret = -EINVAL; + goto unlock_up_free; + } + + i = 0; + IPT_ENTRY_ITERATE(t->private->entries, + t->private->size, + add_counter_to_entry, + paddc->counters, + &i); + unlock_up_free: + write_unlock_bh(&t->lock); + up(&ipt_mutex); + free: + vfree(paddc); + + return ret; +} + +static int +do_ipt_set_ctl(struct sock *sk, int cmd, void *user, unsigned int len) +{ + int ret; + + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + + switch (cmd) { + case IPT_SO_SET_REPLACE: + ret = do_replace(user, len); + break; + + case IPT_SO_SET_ADD_COUNTERS: + ret = do_add_counters(user, len); + break; + + default: + duprintf("do_ipt_set_ctl: unknown request %i\n", cmd); + ret = -EINVAL; + } + + return ret; +} + +static int +do_ipt_get_ctl(struct sock *sk, int cmd, void *user, int *len) +{ + int ret; + + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + + switch (cmd) { + case IPT_SO_GET_INFO: { + char name[IPT_TABLE_MAXNAMELEN]; + struct ipt_table *t; + + if (*len != sizeof(struct ipt_getinfo)) { + duprintf("length %u != %u\n", *len, + sizeof(struct ipt_getinfo)); + ret = -EINVAL; + break; + } + + if (copy_from_user(name, user, sizeof(name)) != 0) { + ret = -EFAULT; + break; + } + name[IPT_TABLE_MAXNAMELEN-1] = '\0'; + t = find_table_lock(name, &ret, &ipt_mutex); + if (t) { + struct ipt_getinfo info; + + info.valid_hooks = t->valid_hooks; + memcpy(info.hook_entry, t->private->hook_entry, + sizeof(info.hook_entry)); + memcpy(info.underflow, t->private->underflow, + sizeof(info.underflow)); + info.num_entries = t->private->number; + info.size = t->private->size; + strcpy(info.name, name); + + if (copy_to_user(user, &info, *len) != 0) + ret = -EFAULT; + else + ret = 0; + + up(&ipt_mutex); + } + } + break; + + case IPT_SO_GET_ENTRIES: { + struct ipt_get_entries get; + + if (*len < sizeof(get)) { + duprintf("get_entries: %u < %u\n", *len, sizeof(get)); + ret = -EINVAL; + } else if (copy_from_user(&get, user, sizeof(get)) != 0) { + ret = -EFAULT; + } else if (*len != sizeof(struct ipt_get_entries) + get.size) { + duprintf("get_entries: %u != %u\n", *len, + sizeof(struct ipt_get_entries) + get.size); + ret = -EINVAL; + } else + ret = get_entries(&get, user); + break; + } + + default: + duprintf("do_ipt_get_ctl: unknown request %i\n", cmd); + ret = -EINVAL; + } + + return ret; +} + +/* Registration hooks for targets. */ +int +ipt_register_target(struct ipt_target *target) +{ + int ret; + + MOD_INC_USE_COUNT; + ret = down_interruptible(&ipt_mutex); + if (ret != 0) { + MOD_DEC_USE_COUNT; + return ret; + } + if (!list_named_insert(&ipt_target, target)) { + duprintf("ipt_register_target: `%s' already in list!\n", + target->name); + ret = -EINVAL; + MOD_DEC_USE_COUNT; + } + up(&ipt_mutex); + return ret; +} + +void +ipt_unregister_target(struct ipt_target *target) +{ + down(&ipt_mutex); + LIST_DELETE(&ipt_target, target); + up(&ipt_mutex); + MOD_DEC_USE_COUNT; +} + +int +ipt_register_match(struct ipt_match *match) +{ + int ret; + + MOD_INC_USE_COUNT; + ret = down_interruptible(&ipt_mutex); + if (ret != 0) { + MOD_DEC_USE_COUNT; + return ret; + } + if (!list_named_insert(&ipt_match, match)) { + duprintf("ipt_register_match: `%s' already in list!\n", + match->name); + MOD_DEC_USE_COUNT; + ret = -EINVAL; + } + up(&ipt_mutex); + + return ret; +} + +void +ipt_unregister_match(struct ipt_match *match) +{ + down(&ipt_mutex); + LIST_DELETE(&ipt_match, match); + up(&ipt_mutex); + MOD_DEC_USE_COUNT; +} + +int ipt_register_table(struct ipt_table *table) +{ + int ret; + struct ipt_table_info *newinfo; + static struct ipt_table_info bootstrap + = { 0, 0, 0, { 0 }, { 0 }, { } }; + + MOD_INC_USE_COUNT; + newinfo = vmalloc(sizeof(struct ipt_table_info) + + SMP_ALIGN(table->table->size) * NR_CPUS); + if (!newinfo) { + ret = -ENOMEM; + MOD_DEC_USE_COUNT; + return ret; + } + memcpy(newinfo->entries, table->table->entries, table->table->size); + + ret = translate_table(table->name, table->valid_hooks, + newinfo, table->table->size, + table->table->num_entries, + table->table->hook_entry, + table->table->underflow); + if (ret != 0) { + vfree(newinfo); + MOD_DEC_USE_COUNT; + return ret; + } + + ret = down_interruptible(&ipt_mutex); + if (ret != 0) { + vfree(newinfo); + MOD_DEC_USE_COUNT; + return ret; + } + + /* Don't autoload: we'd eat our tail... */ + if (list_named_find(&ipt_tables, table->name)) { + ret = -EEXIST; + goto free_unlock; + } + + /* Simplifies replace_table code. */ + table->private = &bootstrap; + if (!replace_table(table, 0, newinfo, &ret)) + goto free_unlock; + + duprintf("table->private->number = %u\n", + table->private->number); + + /* save number of initial entries */ + table->private->initial_entries = table->private->number; + + table->lock = RW_LOCK_UNLOCKED; + list_prepend(&ipt_tables, table); + + unlock: + up(&ipt_mutex); + return ret; + + free_unlock: + vfree(newinfo); + MOD_DEC_USE_COUNT; + goto unlock; +} + +void ipt_unregister_table(struct ipt_table *table) +{ + down(&ipt_mutex); + LIST_DELETE(&ipt_tables, table); + up(&ipt_mutex); + + /* Decrease module usage counts and free resources */ + IPT_ENTRY_ITERATE(table->private->entries, table->private->size, + cleanup_entry, NULL); + vfree(table->private); + MOD_DEC_USE_COUNT; +} + +/* Returns 1 if the port is matched by the range, 0 otherwise */ +static inline int +port_match(u_int16_t min, u_int16_t max, u_int16_t port, int invert) +{ + int ret; + + ret = (port >= min && port <= max) ^ invert; + return ret; +} + +static int +tcp_find_option(u_int8_t option, + const struct tcphdr *tcp, + u_int16_t datalen, + int invert, + int *hotdrop) +{ + unsigned int i = sizeof(struct tcphdr); + const u_int8_t *opt = (u_int8_t *)tcp; + + duprintf("tcp_match: finding option\n"); + /* If we don't have the whole header, drop packet. */ + if (tcp->doff * 4 > datalen) { + *hotdrop = 1; + return 0; + } + + while (i < tcp->doff * 4) { + if (opt[i] == option) return !invert; + if (opt[i] < 2) i++; + else i += opt[i+1]?:1; + } + + return invert; +} + +static int +tcp_match(const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + const void *matchinfo, + int offset, + const void *hdr, + u_int16_t datalen, + int *hotdrop) +{ + const struct tcphdr *tcp = hdr; + const struct ipt_tcp *tcpinfo = matchinfo; + + /* To quote Alan: + + Don't allow a fragment of TCP 8 bytes in. Nobody normal + causes this. Its a cracker trying to break in by doing a + flag overwrite to pass the direction checks. + */ + + if (offset == 1) { + duprintf("Dropping evil TCP offset=1 frag.\n"); + *hotdrop = 1; + return 0; + } else if (offset == 0 && datalen < sizeof(struct tcphdr)) { + /* We've been asked to examine this packet, and we + can't. Hence, no choice but to drop. */ + duprintf("Dropping evil TCP offset=0 tinygram.\n"); + *hotdrop = 1; + return 0; + } + + /* FIXME: Try tcp doff >> packet len against various stacks --RR */ + +#define FWINVTCP(bool,invflg) ((bool) ^ !!(tcpinfo->invflags & invflg)) + + /* Must not be a fragment. */ + return !offset + && port_match(tcpinfo->spts[0], tcpinfo->spts[1], + ntohs(tcp->source), + !!(tcpinfo->invflags & IPT_TCP_INV_SRCPT)) + && port_match(tcpinfo->dpts[0], tcpinfo->dpts[1], + ntohs(tcp->dest), + !!(tcpinfo->invflags & IPT_TCP_INV_DSTPT)) + && FWINVTCP((((unsigned char *)tcp)[13] + & tcpinfo->flg_mask) + == tcpinfo->flg_cmp, + IPT_TCP_INV_FLAGS) + && (!tcpinfo->option + || tcp_find_option(tcpinfo->option, tcp, datalen, + tcpinfo->invflags + & IPT_TCP_INV_OPTION, + hotdrop)); +} + +/* Called when user tries to insert an entry of this type. */ +static int +tcp_checkentry(const char *tablename, + const struct ipt_ip *ip, + void *matchinfo, + unsigned int matchsize, + unsigned int hook_mask) +{ + const struct ipt_tcp *tcpinfo = matchinfo; + + /* Must specify proto == TCP, and no unknown invflags */ + return ip->proto == IPPROTO_TCP + && !(ip->invflags & IPT_INV_PROTO) + && matchsize == IPT_ALIGN(sizeof(struct ipt_tcp)) + && !(tcpinfo->invflags & ~IPT_TCP_INV_MASK); +} + +static int +udp_match(const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + const void *matchinfo, + int offset, + const void *hdr, + u_int16_t datalen, + int *hotdrop) +{ + const struct udphdr *udp = hdr; + const struct ipt_udp *udpinfo = matchinfo; + + if (offset == 0 && datalen < sizeof(struct udphdr)) { + /* We've been asked to examine this packet, and we + can't. Hence, no choice but to drop. */ + duprintf("Dropping evil UDP tinygram.\n"); + *hotdrop = 1; + return 0; + } + + /* Must not be a fragment. */ + return !offset + && port_match(udpinfo->spts[0], udpinfo->spts[1], + ntohs(udp->source), + !!(udpinfo->invflags & IPT_UDP_INV_SRCPT)) + && port_match(udpinfo->dpts[0], udpinfo->dpts[1], + ntohs(udp->dest), + !!(udpinfo->invflags & IPT_UDP_INV_DSTPT)); +} + +/* Called when user tries to insert an entry of this type. */ +static int +udp_checkentry(const char *tablename, + const struct ipt_ip *ip, + void *matchinfo, + unsigned int matchinfosize, + unsigned int hook_mask) +{ + const struct ipt_udp *udpinfo = matchinfo; + + /* Must specify proto == UDP, and no unknown invflags */ + if (ip->proto != IPPROTO_UDP || (ip->invflags & IPT_INV_PROTO)) { + duprintf("ipt_udp: Protocol %u != %u\n", ip->proto, + IPPROTO_UDP); + return 0; + } + if (matchinfosize != IPT_ALIGN(sizeof(struct ipt_udp))) { + duprintf("ipt_udp: matchsize %u != %u\n", + matchinfosize, IPT_ALIGN(sizeof(struct ipt_udp))); + return 0; + } + if (udpinfo->invflags & ~IPT_UDP_INV_MASK) { + duprintf("ipt_udp: unknown flags %X\n", + udpinfo->invflags); + return 0; + } + + return 1; +} + +/* Returns 1 if the type and code is matched by the range, 0 otherwise */ +static inline int +icmp_type_code_match(u_int8_t test_type, u_int8_t min_code, u_int8_t max_code, + u_int8_t type, u_int8_t code, + int invert) +{ + return (type == test_type && code >= min_code && code <= max_code) + ^ invert; +} + +static int +icmp_match(const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + const void *matchinfo, + int offset, + const void *hdr, + u_int16_t datalen, + int *hotdrop) +{ + const struct icmphdr *icmp = hdr; + const struct ipt_icmp *icmpinfo = matchinfo; + + if (offset == 0 && datalen < 2) { + /* We've been asked to examine this packet, and we + can't. Hence, no choice but to drop. */ + duprintf("Dropping evil ICMP tinygram.\n"); + *hotdrop = 1; + return 0; + } + + /* Must not be a fragment. */ + return !offset + && icmp_type_code_match(icmpinfo->type, + icmpinfo->code[0], + icmpinfo->code[1], + icmp->type, icmp->code, + !!(icmpinfo->invflags&IPT_ICMP_INV)); +} + +/* Called when user tries to insert an entry of this type. */ +static int +icmp_checkentry(const char *tablename, + const struct ipt_ip *ip, + void *matchinfo, + unsigned int matchsize, + unsigned int hook_mask) +{ + const struct ipt_icmp *icmpinfo = matchinfo; + + /* Must specify proto == ICMP, and no unknown invflags */ + return ip->proto == IPPROTO_ICMP + && !(ip->invflags & IPT_INV_PROTO) + && matchsize == IPT_ALIGN(sizeof(struct ipt_icmp)) + && !(icmpinfo->invflags & ~IPT_ICMP_INV); +} + +/* The built-in targets: standard (NULL) and error. */ +static struct ipt_target ipt_standard_target += { { NULL, NULL }, IPT_STANDARD_TARGET, NULL, NULL, NULL }; +static struct ipt_target ipt_error_target += { { NULL, NULL }, IPT_ERROR_TARGET, ipt_error, NULL, NULL }; + +static struct nf_sockopt_ops ipt_sockopts += { { NULL, NULL }, PF_INET, IPT_BASE_CTL, IPT_SO_SET_MAX+1, do_ipt_set_ctl, + IPT_BASE_CTL, IPT_SO_GET_MAX+1, do_ipt_get_ctl, 0, NULL }; + +static struct ipt_match tcp_matchstruct += { { NULL, NULL }, "tcp", &tcp_match, &tcp_checkentry, NULL }; +static struct ipt_match udp_matchstruct += { { NULL, NULL }, "udp", &udp_match, &udp_checkentry, NULL }; +static struct ipt_match icmp_matchstruct += { { NULL, NULL }, "icmp", &icmp_match, &icmp_checkentry, NULL }; + +#ifdef CONFIG_PROC_FS +static inline int print_name(const struct ipt_table *t, + off_t start_offset, char *buffer, int length, + off_t *pos, unsigned int *count) +{ + if ((*count)++ >= start_offset) { + unsigned int namelen; + + namelen = sprintf(buffer + *pos, "%s\n", t->name); + if (*pos + namelen > length) { + /* Stop iterating */ + return 1; + } + *pos += namelen; + } + return 0; +} + +static int ipt_get_tables(char *buffer, char **start, off_t offset, int length) +{ + off_t pos = 0; + unsigned int count = 0; + + if (down_interruptible(&ipt_mutex) != 0) + return 0; + + LIST_FIND(&ipt_tables, print_name, struct ipt_table *, + offset, buffer, length, &pos, &count); + + up(&ipt_mutex); + + /* `start' hack - see fs/proc/generic.c line ~105 */ + *start=(char *)((unsigned long)count-offset); + return pos; +} +#endif /*CONFIG_PROC_FS*/ + +static int __init init(void) +{ + int ret; + + /* Noone else will be downing sem now, so we won't sleep */ + down(&ipt_mutex); + list_append(&ipt_target, &ipt_standard_target); + list_append(&ipt_target, &ipt_error_target); + list_append(&ipt_match, &tcp_matchstruct); + list_append(&ipt_match, &udp_matchstruct); + list_append(&ipt_match, &icmp_matchstruct); + up(&ipt_mutex); + + /* Register setsockopt */ + ret = nf_register_sockopt(&ipt_sockopts); + if (ret < 0) { + duprintf("Unable to register sockopts.\n"); + return ret; + } + +#ifdef CONFIG_PROC_FS + { + struct proc_dir_entry *proc; + + proc = proc_net_create("ip_tables_names", 0, ipt_get_tables); + if (!proc) { + nf_unregister_sockopt(&ipt_sockopts); + return -ENOMEM; + } + proc->owner = THIS_MODULE; + } +#endif + + printk("ip_tables: (C) 2000-2002 Netfilter core team\n"); + return 0; +} + +static void __exit fini(void) +{ + nf_unregister_sockopt(&ipt_sockopts); +#ifdef CONFIG_PROC_FS + proc_net_remove("ip_tables_names"); +#endif +} + +EXPORT_SYMBOL(ipt_register_table); +EXPORT_SYMBOL(ipt_unregister_table); +EXPORT_SYMBOL(ipt_register_match); +EXPORT_SYMBOL(ipt_unregister_match); +EXPORT_SYMBOL(ipt_do_table); +EXPORT_SYMBOL(ipt_register_target); +EXPORT_SYMBOL(ipt_unregister_target); + +module_init(init); +module_exit(fini); +MODULE_LICENSE("GPL"); |