diff options
Diffstat (limited to 'src/helpers')
| -rw-r--r-- | src/helpers/Makefile.am | 7 | ||||
| -rw-r--r-- | src/helpers/dhcpv6.c | 123 |
2 files changed, 129 insertions, 1 deletions
diff --git a/src/helpers/Makefile.am b/src/helpers/Makefile.am index 589b4f3..59524f5 100644 --- a/src/helpers/Makefile.am +++ b/src/helpers/Makefile.am @@ -1,9 +1,14 @@ include $(top_srcdir)/Make_global.am -pkglib_LTLIBRARIES = ct_helper_ftp.la \ +pkglib_LTLIBRARIES = ct_helper_dhcpv6.la \ + ct_helper_ftp.la \ ct_helper_rpc.la \ ct_helper_tns.la +ct_helper_dhcpv6_la_SOURCES = dhcpv6.c +ct_helper_dhcpv6_la_LDFLAGS = -avoid-version -module $(LIBNETFILTER_CONNTRACK_LIBS) +ct_helper_dhcpv6_la_CFLAGS = $(AM_CFLAGS) $(LIBNETFILTER_CONNTRACK_CFLAGS) + ct_helper_ftp_la_SOURCES = ftp.c ct_helper_ftp_la_LDFLAGS = -avoid-version -module $(LIBNETFILTER_CONNTRACK_LIBS) ct_helper_ftp_la_CFLAGS = $(AM_CFLAGS) $(LIBNETFILTER_CONNTRACK_CFLAGS) diff --git a/src/helpers/dhcpv6.c b/src/helpers/dhcpv6.c new file mode 100644 index 0000000..73632ec --- /dev/null +++ b/src/helpers/dhcpv6.c @@ -0,0 +1,123 @@ +/* + * (C) 2013 by Pablo Neira Ayuso <pablo@netfilter.org> + * + * Adapted from: + * + * DHCPv6 multicast connection tracking helper. + * + * (c) 2012 Google Inc. + * + * Original author: Darren Willis <djw@google.com> + * + * 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 "conntrackd.h" +#include "helper.h" +#include "myct.h" +#include "log.h" +#include <errno.h> +#include <netinet/ip.h> +#include <netinet/ip6.h> +#include <netinet/udp.h> +#include <libmnl/libmnl.h> +#include <libnetfilter_conntrack/libnetfilter_conntrack.h> +#include <libnetfilter_queue/libnetfilter_queue.h> +#include <libnetfilter_queue/libnetfilter_queue_udp.h> +#include <libnetfilter_queue/pktbuff.h> +#include <linux/netfilter.h> + +#define DHCPV6_CLIENT_PORT 546 + +static uint16_t dhcpv6_port; + +/* Timeouts for DHCPv6 replies, in seconds, indexed by message type. */ +static const int dhcpv6_timeouts[] = { + 0, /* No message has type 0. */ + 120, /* Solicit. */ + 0, /* Advertise. */ + 30, /* Request. */ + 4, /* Confirm. */ + 600, /* Renew. */ + 600, /* Rebind. */ + 0, /* Reply. */ + 1, /* Release. */ + 1, /* Decline. */ + 0, /* Reconfigure. */ + 120, /* Information Request. */ + 0, /* Relay-forward. */ + 0 /* Relay-reply. */ +}; + +static inline int ipv6_addr_is_multicast(const struct in6_addr *addr) +{ + return (addr->s6_addr32[0] & htonl(0xFF000000)) == htonl(0xFF000000); +} + +static int +dhcpv6_helper_cb(struct pkt_buff *pkt, uint32_t protoff, + struct myct *myct, uint32_t ctinfo) +{ + struct iphdr *iph = (struct iphdr *)pktb_network_header(pkt); + struct ip6_hdr *ip6h = (struct ip6_hdr *)pktb_network_header(pkt); + int dir = CTINFO2DIR(ctinfo); + union nfct_attr_grp_addr addr; + struct nf_expect *exp; + uint8_t *dhcpv6_msg_type; + + if (iph->version != 6 || !ipv6_addr_is_multicast(&ip6h->ip6_dst)) + return NF_ACCEPT; + + dhcpv6_msg_type = pktb_network_header(pkt) + protoff + sizeof(struct udphdr); + if (*dhcpv6_msg_type > ARRAY_SIZE(dhcpv6_timeouts)) { + printf("Dropping DHCPv6 message with bad type %u\n", + *dhcpv6_msg_type); + return NF_DROP; + } + + exp = nfexp_new(); + if (exp == NULL) + return NF_ACCEPT; + + cthelper_get_addr_src(myct->ct, dir, &addr); + + if (cthelper_expect_init(exp, myct->ct, 0, NULL, &addr, + IPPROTO_UDP, NULL, &dhcpv6_port, + NF_CT_EXPECT_PERMANENT)) { + nfexp_destroy(exp); + return NF_DROP; + } + + myct->exp = exp; + + if (dhcpv6_timeouts[*dhcpv6_msg_type] > 0) { + nfct_set_attr_u32(myct->ct, ATTR_TIMEOUT, + dhcpv6_timeouts[*dhcpv6_msg_type]); + } + + return NF_ACCEPT; +} + +static struct ctd_helper dhcpv6_helper = { + .name = "dhcpv6", + .l4proto = IPPROTO_UDP, + .cb = dhcpv6_helper_cb, + .policy = { + [0] = { + .name = "dhcpv6", + .expect_max = 1, + .expect_timeout = 300, + }, + }, +}; + +void __attribute__ ((constructor)) dhcpv6_init(void); + +void dhcpv6_init(void) +{ + dhcpv6_port = htons(DHCPV6_CLIENT_PORT); + helper_register(&dhcpv6_helper); +} |