diff options
Diffstat (limited to 'src/deprecated/extensions/libnetfilter_conntrack_tcp.c')
| -rw-r--r-- | src/deprecated/extensions/libnetfilter_conntrack_tcp.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/src/deprecated/extensions/libnetfilter_conntrack_tcp.c b/src/deprecated/extensions/libnetfilter_conntrack_tcp.c new file mode 100644 index 0000000..9efdbb7 --- /dev/null +++ b/src/deprecated/extensions/libnetfilter_conntrack_tcp.c @@ -0,0 +1,142 @@ +/* + * (C) 2005 by Pablo Neira Ayuso <pablo@netfilter.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + */ +#include <stdio.h> +#include <getopt.h> +#include <stdlib.h> +#include <string.h> +#include <netinet/in.h> /* For htons */ +#include <libnetfilter_conntrack/linux_nfnetlink_conntrack.h> +#include <libnetfilter_conntrack/libnetfilter_conntrack.h> +#include <libnetfilter_conntrack/libnetfilter_conntrack_extensions.h> +#include <libnetfilter_conntrack/libnetfilter_conntrack_tcp.h> + +static const char *states[] = { + "NONE", + "SYN_SENT", + "SYN_RECV", + "ESTABLISHED", + "FIN_WAIT", + "CLOSE_WAIT", + "LAST_ACK", + "TIME_WAIT", + "CLOSE", + "LISTEN" +}; + +static void parse_proto(struct nfattr *cda[], struct nfct_tuple *tuple) +{ + if (cda[CTA_PROTO_SRC_PORT-1]) + tuple->l4src.tcp.port = + *(u_int16_t *)NFA_DATA(cda[CTA_PROTO_SRC_PORT-1]); + if (cda[CTA_PROTO_DST_PORT-1]) + tuple->l4dst.tcp.port = + *(u_int16_t *)NFA_DATA(cda[CTA_PROTO_DST_PORT-1]); +} + +static void parse_protoinfo(struct nfattr *cda[], struct nfct_conntrack *ct) +{ + struct nfattr *tb[CTA_PROTOINFO_TCP_MAX]; + + /* + * Listen to me carefully: This is easy to trigger with events ;). + * The conntrack event messages don't always contain all the + * information about a conntrack, just those fields that have changed. + * So you can receive a message about a TCP connection with no bits + * talking about the private protocol information. + * + * --pablo 05/10/31 + */ + if (!cda[CTA_PROTOINFO_TCP-1]) + return; + + nfnl_parse_nested(tb,CTA_PROTOINFO_TCP_MAX, cda[CTA_PROTOINFO_TCP-1]); + + if (tb[CTA_PROTOINFO_TCP_STATE-1]) + ct->protoinfo.tcp.state = + *(u_int8_t *)NFA_DATA(tb[CTA_PROTOINFO_TCP_STATE-1]); +} + +static void build_tuple_proto(struct nfnlhdr *req, int size, + struct nfct_tuple *t) +{ + nfnl_addattr_l(&req->nlh, size, CTA_PROTO_SRC_PORT, + &t->l4src.tcp.port, sizeof(u_int16_t)); + nfnl_addattr_l(&req->nlh, size, CTA_PROTO_DST_PORT, + &t->l4dst.tcp.port, sizeof(u_int16_t)); +} + +static void build_protoinfo(struct nfnlhdr *req, int size, + struct nfct_conntrack *ct) +{ + struct nfattr *nest_proto; + + nest_proto = nfnl_nest(&req->nlh, size, CTA_PROTOINFO_TCP); + nfnl_addattr_l(&req->nlh, size, CTA_PROTOINFO_TCP_STATE, + &ct->protoinfo.tcp.state, sizeof(u_int8_t)); + nfnl_nest_end(&req->nlh, nest_proto); +} + +static int print_protoinfo(char *buf, union nfct_protoinfo *protoinfo) +{ + return(sprintf(buf, "%s ", states[protoinfo->tcp.state])); +} + +static int print_proto(char *buf, struct nfct_tuple *tuple) +{ + return(sprintf(buf, "sport=%u dport=%u ", htons(tuple->l4src.tcp.port), + htons(tuple->l4dst.tcp.port))); +} + +static int compare(struct nfct_conntrack *ct1, + struct nfct_conntrack *ct2, + unsigned int flags) +{ + if (flags & TCP_ORIG_SPORT) + if (ct1->tuple[NFCT_DIR_ORIGINAL].l4src.tcp.port != + ct2->tuple[NFCT_DIR_ORIGINAL].l4src.tcp.port) + return 0; + if (flags & TCP_ORIG_DPORT) + if (ct1->tuple[NFCT_DIR_ORIGINAL].l4dst.tcp.port != + ct2->tuple[NFCT_DIR_ORIGINAL].l4dst.tcp.port) + return 0; + if (flags & TCP_REPL_SPORT) + if (ct1->tuple[NFCT_DIR_REPLY].l4src.tcp.port != + ct2->tuple[NFCT_DIR_REPLY].l4src.tcp.port) + return 0; + if (flags & TCP_REPL_DPORT) + if (ct1->tuple[NFCT_DIR_REPLY].l4dst.tcp.port != + ct2->tuple[NFCT_DIR_REPLY].l4dst.tcp.port) + return 0; + if (flags & TCP_STATE) + if (ct1->protoinfo.tcp.state != ct2->protoinfo.tcp.state) + return 0; + + return 1; +} + +static struct nfct_proto tcp = { + .name = "tcp", + .protonum = IPPROTO_TCP, + .parse_protoinfo = parse_protoinfo, + .parse_proto = parse_proto, + .build_tuple_proto = build_tuple_proto, + .build_protoinfo = build_protoinfo, + .print_protoinfo = print_protoinfo, + .print_proto = print_proto, + .compare = compare, + .version = VERSION +}; + +static void __attribute__ ((constructor)) init(void); + +static void init(void) +{ + nfct_register_proto(&tcp); +} |