From aa55e1345bb84993273fabe4680a08b48fa99944 Mon Sep 17 00:00:00 2001 From: gborowiak Date: Tue, 16 Sep 2003 19:26:38 +0000 Subject: changed the structure of the hash table reedited to 80col/8tab and K-R indent 0.0.0.0 IP address is now illegal --- kernel/linux2.5/net/bridge/netfilter/ebt_among.c | 212 +++++++++++++++++------ 1 file changed, 161 insertions(+), 51 deletions(-) (limited to 'kernel/linux2.5/net/bridge') diff --git a/kernel/linux2.5/net/bridge/netfilter/ebt_among.c b/kernel/linux2.5/net/bridge/netfilter/ebt_among.c index 1ae9ad4..e4b2268 100644 --- a/kernel/linux2.5/net/bridge/netfilter/ebt_among.c +++ b/kernel/linux2.5/net/bridge/netfilter/ebt_among.c @@ -10,100 +10,209 @@ #include #include +#include +#include #include -static int ebt_mac_wormhash_contains(const struct ebt_mac_wormhash *wh, const char *mac) +/* +#define DEBUG +*/ + +static int ebt_mac_wormhash_contains(const struct ebt_mac_wormhash *wh, + const char *mac, uint32_t ip) { /* You may be puzzled as to how this code works. - * Some tricks were used, refer to include/linux/netfilter_bridge/ebt_among.h + * Some tricks were used, refer to + * include/linux/netfilter_bridge/ebt_among.h * as there you can find a solution of this mystery. */ const struct ebt_mac_wormhash_tuple *p; - int offset; - const char *base = (const char*)wh; + int start, limit, i; uint32_t cmp[2] = { 0, 0 }; - int key = (const unsigned char)mac[5]; - memcpy(((char*)cmp)+2, mac, 6); - offset = wh->table[key]; - while (offset) { - p = (const struct ebt_mac_wormhash_tuple*)(base + offset); - if (cmp[1] == p->cmp[1] && cmp[0] == p->cmp[0]) - return 1; - offset = p->next_ofs; + int key = (const unsigned char) mac[5]; + memcpy(((char *) cmp) + 2, mac, 6); + start = wh->table[key]; + limit = wh->table[key + 1]; + if (ip) { + for (i = start; i < limit; i++) { + p = &wh->pool[i]; + if (cmp[1] == p->cmp[1] && cmp[0] == p->cmp[0]) { + if (p->ip == 0 || p->ip == ip) { + return 1; + } + } + } + } else { + for (i = start; i < limit; i++) { + p = &wh->pool[i]; + if (cmp[1] == p->cmp[1] && cmp[0] == p->cmp[0]) { + return 1; + } + } } return 0; } -static int ebt_mac_wormhash_check_integrity(const struct ebt_mac_wormhash *wh) +static int ebt_mac_wormhash_check_integrity(const struct ebt_mac_wormhash + *wh) { - int i, count; - const struct ebt_mac_wormhash_tuple *p; - int offset; - const char *base = (const char*)wh; - - count = 0; - for (i=256; i--;) { - offset = wh->table[i]; - while (offset) { - p = (const struct ebt_mac_wormhash_tuple*)(base + offset); - if (p < wh->pool) - return -1; - if (p > wh->pool + 256 - 1) - return -2; - count++; - if (count > 1000) - return -3; - offset = p->next_ofs; - } + int i; + for (i=0; i<256; i++) { + if (wh->table[i] > wh->table[i + 1]) + return -0x100 - i; + if (wh->table[i] < 0) + return -0x200 - i; + if (wh->table[i] > wh->poolsize) + return -0x300 - i; + } + if (wh->table[256] > wh->poolsize) + return -0xc00; + return 0; +} + +static int get_ip_dst(const struct sk_buff *skb, uint32_t * addr) +{ + if (skb->mac.ethernet->h_proto == __constant_htons(ETH_P_IP)) { + *addr = skb->nh.iph->daddr; + return 1; + } + if (skb->mac.ethernet->h_proto == __constant_htons(ETH_P_ARP)) { + + uint32_t arp_len = sizeof(struct arphdr) + + (2 * (((*skb).nh.arph)->ar_hln)) + + (2 * (((*skb).nh.arph)->ar_pln)); + + /* Make sure the packet is long enough. */ + if ((((*skb).nh.raw) + arp_len) > (*skb).tail) + return 0; + /* IPv4 addresses are always 4 bytes. */ + if (((*skb).nh.arph)->ar_pln != sizeof(uint32_t)) + return 0; + + memcpy(addr, ((*skb).nh.raw) + sizeof(struct arphdr) + + (2 * (((*skb).nh.arph)->ar_hln)) + + (((*skb).nh.arph)->ar_pln), sizeof(uint32_t)); + + return 2; + } + return 0; +} + +static int get_ip_src(const struct sk_buff *skb, uint32_t * addr) +{ + if (skb->mac.ethernet->h_proto == __constant_htons(ETH_P_IP)) { + *addr = skb->nh.iph->saddr; + return 1; + } + if (skb->mac.ethernet->h_proto == __constant_htons(ETH_P_ARP)) { + + uint32_t arp_len = sizeof(struct arphdr) + + (2 * (((*skb).nh.arph)->ar_hln)) + + (2 * (((*skb).nh.arph)->ar_pln)); + + /* Make sure the packet is long enough. */ + if ((((*skb).nh.raw) + arp_len) > (*skb).tail) + return 0; + /* IPv4 addresses are always 4 bytes. */ + if (((*skb).nh.arph)->ar_pln != sizeof(uint32_t)) + return 0; + + memcpy(addr, ((*skb).nh.raw) + sizeof(struct arphdr) + + ((((*skb).nh.arph)->ar_hln)), sizeof(uint32_t)); + + return 2; } return 0; } static int ebt_filter_among(const struct sk_buff *skb, - const struct net_device *in, const struct net_device *out, const void *data, - unsigned int datalen) + const struct net_device *in, + const struct net_device *out, const void *data, + unsigned int datalen) { struct ebt_among_info *info = (struct ebt_among_info *) data; - const char *dmac, *smac; - if (info->bitmask & EBT_AMONG_SRC) { + const struct ebt_mac_wormhash *wh_dst, *wh_src; + uint32_t dip = 0, sip = 0; + + wh_dst = ebt_among_wh_dst(info); + wh_src = ebt_among_wh_src(info); + + if (wh_src) { smac = skb->mac.ethernet->h_source; - if (!ebt_mac_wormhash_contains(&info->wh_src, smac)) - return EBT_NOMATCH; + get_ip_src(skb, &sip); + if (!(info->bitmask & EBT_AMONG_SRC_NEG)) { + /* we match only if it contains */ + if (!ebt_mac_wormhash_contains(wh_src, smac, sip)) { + return EBT_NOMATCH; + } + } else { + /* we match only if it DOES NOT contain */ + if (ebt_mac_wormhash_contains(wh_src, smac, sip)) { + return EBT_NOMATCH; + } + } } - if (info->bitmask & EBT_AMONG_DST) { + if (wh_dst) { dmac = skb->mac.ethernet->h_dest; - if (!ebt_mac_wormhash_contains(&info->wh_dst, dmac)) - return EBT_NOMATCH; + get_ip_dst(skb, &dip); + if (!(info->bitmask & EBT_AMONG_DST_NEG)) { + /* we match only if it contains */ + if (!ebt_mac_wormhash_contains(wh_dst, dmac, dip)) { + return EBT_NOMATCH; + } + } else { + /* we match only if it DOES NOT contain */ + if (ebt_mac_wormhash_contains(wh_dst, dmac, dip)) { + return EBT_NOMATCH; + } + } } return EBT_MATCH; } static int ebt_among_check(const char *tablename, unsigned int hookmask, - const struct ebt_entry *e, void *data, unsigned int datalen) + const struct ebt_entry *e, void *data, + unsigned int datalen) { struct ebt_among_info *info = (struct ebt_among_info *) data; + int expected_length = sizeof(struct ebt_among_info); + const struct ebt_mac_wormhash *wh_dst, *wh_src; + int err; + wh_dst = ebt_among_wh_dst(info); + wh_src = ebt_among_wh_src(info); + expected_length += ebt_mac_wormhash_size(wh_dst); + expected_length += ebt_mac_wormhash_size(wh_src); - if (datalen != EBT_ALIGN(sizeof(struct ebt_among_info))) { - printk(KERN_WARNING "ebtables: among: wrong size\n"); + if (datalen < EBT_ALIGN(expected_length)) { + printk(KERN_WARNING + "ebtables: among: wrong size: %d" + "against expected %d, rounded to %d\n", + datalen, expected_length, + EBT_ALIGN(expected_length)); return -EINVAL; } - if ((info->bitmask & EBT_AMONG_DST) && ebt_mac_wormhash_check_integrity(&info->wh_dst)) { - printk(KERN_WARNING "ebtables: among: dst integrity fail\n"); + if (wh_dst && (err = ebt_mac_wormhash_check_integrity(wh_dst))) { + printk(KERN_WARNING + "ebtables: among: dst integrity fail: %x\n", -err); return -EINVAL; } - if ((info->bitmask & EBT_AMONG_SRC) && ebt_mac_wormhash_check_integrity(&info->wh_src)) { - printk(KERN_WARNING "ebtables: among: src integrity fail\n"); + if (wh_src && (err = ebt_mac_wormhash_check_integrity(wh_src))) { + printk(KERN_WARNING + "ebtables: among: src integrity fail: %x\n", -err); return -EINVAL; } return 0; } -static struct ebt_match filter_among = -{ - {NULL, NULL}, EBT_AMONG_MATCH, ebt_filter_among, ebt_among_check, NULL, +static struct ebt_match filter_among = { + {NULL, NULL}, + EBT_AMONG_MATCH, + ebt_filter_among, + ebt_among_check, + NULL, THIS_MODULE }; @@ -119,4 +228,5 @@ static void __exit fini(void) module_init(init); module_exit(fini); +EXPORT_NO_SYMBOLS; MODULE_LICENSE("GPL"); -- cgit v1.2.3