From 2e4e6a17af35be359cc8f1c924f8f198fbd478cc Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Thu, 12 Jan 2006 13:30:04 -0800 Subject: [NETFILTER] x_tables: Abstraction layer for {ip,ip6,arp}_tables This monster-patch tries to do the best job for unifying the data structures and backend interfaces for the three evil clones ip_tables, ip6_tables and arp_tables. In an ideal world we would never have allowed this kind of copy+paste programming... but well, our world isn't (yet?) ideal. o introduce a new x_tables module o {ip,arp,ip6}_tables depend on this x_tables module o registration functions for tables, matches and targets are only wrappers around x_tables provided functions o all matches/targets that are used from ip_tables and ip6_tables are now implemented as xt_FOOBAR.c files and provide module aliases to ipt_FOOBAR and ip6t_FOOBAR o header files for xt_matches are in include/linux/netfilter/, include/linux/netfilter_{ipv4,ipv6} contains compatibility wrappers around the xt_FOOBAR.h headers Based on this patchset we're going to further unify the code, gradually getting rid of all the layer 3 specific assumptions. Signed-off-by: Harald Welte Signed-off-by: David S. Miller --- net/netfilter/xt_sctp.c | 250 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 250 insertions(+) create mode 100644 net/netfilter/xt_sctp.c (limited to 'net/netfilter/xt_sctp.c') diff --git a/net/netfilter/xt_sctp.c b/net/netfilter/xt_sctp.c new file mode 100644 index 000000000000..10fbfc5ba758 --- /dev/null +++ b/net/netfilter/xt_sctp.c @@ -0,0 +1,250 @@ +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Kiran Kumar Immidi"); +MODULE_DESCRIPTION("Match for SCTP protocol packets"); +MODULE_ALIAS("ipt_sctp"); + +#ifdef DEBUG_SCTP +#define duprintf(format, args...) printk(format , ## args) +#else +#define duprintf(format, args...) +#endif + +#define SCCHECK(cond, option, flag, invflag) (!((flag) & (option)) \ + || (!!((invflag) & (option)) ^ (cond))) + +static int +match_flags(const struct xt_sctp_flag_info *flag_info, + const int flag_count, + u_int8_t chunktype, + u_int8_t chunkflags) +{ + int i; + + for (i = 0; i < flag_count; i++) { + if (flag_info[i].chunktype == chunktype) { + return (chunkflags & flag_info[i].flag_mask) == flag_info[i].flag; + } + } + + return 1; +} + +static inline int +match_packet(const struct sk_buff *skb, + unsigned int offset, + const u_int32_t *chunkmap, + int chunk_match_type, + const struct xt_sctp_flag_info *flag_info, + const int flag_count, + int *hotdrop) +{ + u_int32_t chunkmapcopy[256 / sizeof (u_int32_t)]; + sctp_chunkhdr_t _sch, *sch; + +#ifdef DEBUG_SCTP + int i = 0; +#endif + + if (chunk_match_type == SCTP_CHUNK_MATCH_ALL) { + SCTP_CHUNKMAP_COPY(chunkmapcopy, chunkmap); + } + + do { + sch = skb_header_pointer(skb, offset, sizeof(_sch), &_sch); + if (sch == NULL) { + duprintf("Dropping invalid SCTP packet.\n"); + *hotdrop = 1; + return 0; + } + + duprintf("Chunk num: %d\toffset: %d\ttype: %d\tlength: %d\tflags: %x\n", + ++i, offset, sch->type, htons(sch->length), sch->flags); + + offset += (htons(sch->length) + 3) & ~3; + + duprintf("skb->len: %d\toffset: %d\n", skb->len, offset); + + if (SCTP_CHUNKMAP_IS_SET(chunkmap, sch->type)) { + switch (chunk_match_type) { + case SCTP_CHUNK_MATCH_ANY: + if (match_flags(flag_info, flag_count, + sch->type, sch->flags)) { + return 1; + } + break; + + case SCTP_CHUNK_MATCH_ALL: + if (match_flags(flag_info, flag_count, + sch->type, sch->flags)) { + SCTP_CHUNKMAP_CLEAR(chunkmapcopy, sch->type); + } + break; + + case SCTP_CHUNK_MATCH_ONLY: + if (!match_flags(flag_info, flag_count, + sch->type, sch->flags)) { + return 0; + } + break; + } + } else { + switch (chunk_match_type) { + case SCTP_CHUNK_MATCH_ONLY: + return 0; + } + } + } while (offset < skb->len); + + switch (chunk_match_type) { + case SCTP_CHUNK_MATCH_ALL: + return SCTP_CHUNKMAP_IS_CLEAR(chunkmap); + case SCTP_CHUNK_MATCH_ANY: + return 0; + case SCTP_CHUNK_MATCH_ONLY: + return 1; + } + + /* This will never be reached, but required to stop compiler whine */ + return 0; +} + +static int +match(const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + const void *matchinfo, + int offset, + unsigned int protoff, + int *hotdrop) +{ + const struct xt_sctp_info *info; + sctp_sctphdr_t _sh, *sh; + + info = (const struct xt_sctp_info *)matchinfo; + + if (offset) { + duprintf("Dropping non-first fragment.. FIXME\n"); + return 0; + } + + sh = skb_header_pointer(skb, protoff, sizeof(_sh), &_sh); + if (sh == NULL) { + duprintf("Dropping evil TCP offset=0 tinygram.\n"); + *hotdrop = 1; + return 0; + } + duprintf("spt: %d\tdpt: %d\n", ntohs(sh->source), ntohs(sh->dest)); + + return SCCHECK(((ntohs(sh->source) >= info->spts[0]) + && (ntohs(sh->source) <= info->spts[1])), + XT_SCTP_SRC_PORTS, info->flags, info->invflags) + && SCCHECK(((ntohs(sh->dest) >= info->dpts[0]) + && (ntohs(sh->dest) <= info->dpts[1])), + XT_SCTP_DEST_PORTS, info->flags, info->invflags) + && SCCHECK(match_packet(skb, protoff, + info->chunkmap, info->chunk_match_type, + info->flag_info, info->flag_count, + hotdrop), + XT_SCTP_CHUNK_TYPES, info->flags, info->invflags); +} + +static int +checkentry(const char *tablename, + const void *inf, + void *matchinfo, + unsigned int matchsize, + unsigned int hook_mask) +{ + const struct xt_sctp_info *info; + const struct ipt_ip *ip = inf; + + info = (const struct xt_sctp_info *)matchinfo; + + return ip->proto == IPPROTO_SCTP + && !(ip->invflags & XT_INV_PROTO) + && matchsize == XT_ALIGN(sizeof(struct xt_sctp_info)) + && !(info->flags & ~XT_SCTP_VALID_FLAGS) + && !(info->invflags & ~XT_SCTP_VALID_FLAGS) + && !(info->invflags & ~info->flags) + && ((!(info->flags & XT_SCTP_CHUNK_TYPES)) || + (info->chunk_match_type & + (SCTP_CHUNK_MATCH_ALL + | SCTP_CHUNK_MATCH_ANY + | SCTP_CHUNK_MATCH_ONLY))); +} + +static int +checkentry6(const char *tablename, + const void *inf, + void *matchinfo, + unsigned int matchsize, + unsigned int hook_mask) +{ + const struct xt_sctp_info *info; + const struct ip6t_ip6 *ip = inf; + + info = (const struct xt_sctp_info *)matchinfo; + + return ip->proto == IPPROTO_SCTP + && !(ip->invflags & XT_INV_PROTO) + && matchsize == XT_ALIGN(sizeof(struct xt_sctp_info)) + && !(info->flags & ~XT_SCTP_VALID_FLAGS) + && !(info->invflags & ~XT_SCTP_VALID_FLAGS) + && !(info->invflags & ~info->flags) + && ((!(info->flags & XT_SCTP_CHUNK_TYPES)) || + (info->chunk_match_type & + (SCTP_CHUNK_MATCH_ALL + | SCTP_CHUNK_MATCH_ANY + | SCTP_CHUNK_MATCH_ONLY))); +} + + +static struct xt_match sctp_match = +{ + .name = "sctp", + .match = &match, + .checkentry = &checkentry, + .me = THIS_MODULE +}; +static struct xt_match sctp6_match = +{ + .name = "sctp", + .match = &match, + .checkentry = &checkentry6, + .me = THIS_MODULE +}; + + +static int __init init(void) +{ + int ret; + ret = xt_register_match(AF_INET, &sctp_match); + if (ret) + return ret; + + ret = xt_register_match(AF_INET6, &sctp6_match); + if (ret) + xt_unregister_match(AF_INET, &sctp_match); + + return ret; +} + +static void __exit fini(void) +{ + xt_unregister_match(AF_INET6, &sctp6_match); + xt_unregister_match(AF_INET, &sctp_match); +} + +module_init(init); +module_exit(fini); -- cgit v1.2.3