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dhcpv6.c
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dhcpv6.c
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/**
* Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License v2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <time.h>
#include <fcntl.h>
#include <errno.h>
#include <stdlib.h>
#include <signal.h>
#include <limits.h>
#include <resolv.h>
#include <string.h>
#include <unistd.h>
#include <syslog.h>
#include <stdbool.h>
#include <ctype.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#include <net/ethernet.h>
#include "odhcp6c.h"
#include "md5.h"
#define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
#define DHCPV6_CLIENT_PORT 546
#define DHCPV6_SERVER_PORT 547
#define DHCPV6_DUID_LLADDR 3
#define DHCPV6_REQ_DELAY 1
#define DHCPV6_SOL_MAX_RT_MIN 60
#define DHCPV6_SOL_MAX_RT_MAX 86400
#define DHCPV6_INF_MAX_RT_MIN 60
#define DHCPV6_INF_MAX_RT_MAX 86400
static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
const uint8_t transaction[3], enum dhcpv6_msg type,
const struct in6_addr *daddr);
static int dhcpv6_parse_ia(void *opt, void *end);
static int dhcpv6_calc_refresh_timers(void);
static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
const uint16_t code, const void *status_msg, const int len,
int *ret);
static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
const void *status_msg, const int len,
bool handled_status_codes[_DHCPV6_Status_Max],
int *ret);
static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
static void dhcpv6_clear_all_server_cand(void);
static reply_handler dhcpv6_handle_reply;
static reply_handler dhcpv6_handle_advert;
static reply_handler dhcpv6_handle_rebind_reply;
static reply_handler dhcpv6_handle_reconfigure;
static int dhcpv6_commit_advert(void);
// RFC 3315 - 5.5 Timeout and Delay values
static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
[DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
dhcpv6_handle_reconfigure, NULL},
[DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
dhcpv6_handle_advert, dhcpv6_commit_advert},
[DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
dhcpv6_handle_reply, NULL},
[DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
dhcpv6_handle_reply, NULL},
[DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
dhcpv6_handle_rebind_reply, NULL},
[DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
[DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
[DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
dhcpv6_handle_reply, NULL},
};
// Sockets
static int sock = -1;
static int ifindex = -1;
static int64_t t1 = 0, t2 = 0, t3 = 0;
// IA states
static int request_prefix = -1;
static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
static bool accept_reconfig = false;
// Reconfigure key
static uint8_t reconf_key[16];
// client options
static unsigned int client_options = 0;
int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
{
client_options = options;
dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
if (sock < 0)
return -1;
// Detect interface
struct ifreq ifr;
strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
return -1;
ifindex = ifr.ifr_ifindex;
// Create client DUID
size_t client_id_len;
odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
if (client_id_len == 0) {
uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
DHCPV6_DUID_LLADDR, 0, 1};
if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
struct ifreq ifs[100], *ifp, *ifend;
struct ifconf ifc;
ifc.ifc_req = ifs;
ifc.ifc_len = sizeof(ifs);
if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
// If our interface doesn't have an address...
ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
for (ifp = ifc.ifc_req; ifp < ifend &&
!memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
memcpy(ifr.ifr_name, ifp->ifr_name,
sizeof(ifr.ifr_name));
if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
continue;
memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
ETHER_ADDR_LEN);
}
}
odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
}
// Create ORO
if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
uint16_t oro[] = {
htons(DHCPV6_OPT_SIP_SERVER_D),
htons(DHCPV6_OPT_SIP_SERVER_A),
htons(DHCPV6_OPT_DNS_SERVERS),
htons(DHCPV6_OPT_DNS_DOMAIN),
htons(DHCPV6_OPT_SNTP_SERVERS),
htons(DHCPV6_OPT_NTP_SERVER),
htons(DHCPV6_OPT_AFTR_NAME),
htons(DHCPV6_OPT_PD_EXCLUDE),
htons(DHCPV6_OPT_SOL_MAX_RT),
htons(DHCPV6_OPT_INF_MAX_RT),
#ifdef EXT_CER_ID
htons(DHCPV6_OPT_CER_ID),
#endif
htons(DHCPV6_OPT_S46_CONT_MAPE),
htons(DHCPV6_OPT_S46_CONT_MAPT),
htons(DHCPV6_OPT_S46_CONT_LW),
};
odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
}
// Configure IPv6-options
int val = 1;
setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
.sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
return -1;
return 0;
}
enum {
IOV_HDR=0,
IOV_ORO,
IOV_ORO_REFRESH,
IOV_CL_ID,
IOV_SRV_ID,
IOV_VENDOR_CLASS_HDR,
IOV_VENDOR_CLASS,
IOV_USER_CLASS_HDR,
IOV_USER_CLASS,
IOV_RECONF_ACCEPT,
IOV_FQDN,
IOV_HDR_IA_NA,
IOV_IA_NA,
IOV_IA_PD,
IOV_TOTAL
};
int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
{
int mode = DHCPV6_UNKNOWN;
na_mode = na;
pd_mode = pd;
if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
mode = DHCPV6_STATELESS;
else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
mode = DHCPV6_STATEFUL;
return mode;
}
static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
{
// Build FQDN
char fqdn_buf[256];
gethostname(fqdn_buf, sizeof(fqdn_buf));
struct {
uint16_t type;
uint16_t len;
uint8_t flags;
uint8_t data[256];
} fqdn;
size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
sizeof(fqdn.data), NULL, NULL);
fqdn.type = htons(DHCPV6_OPT_FQDN);
fqdn.len = htons(fqdn_len - 4);
fqdn.flags = 0;
// Build Client ID
size_t cl_id_len;
void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
// Get Server ID
size_t srv_id_len;
void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
// Build IA_PDs
size_t ia_pd_entries = 0, ia_pd_len = 0;
uint8_t *ia_pd;
if (type == DHCPV6_MSG_SOLICIT) {
odhcp6c_clear_state(STATE_IA_PD);
size_t n_prefixes;
struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
n_prefixes /= sizeof(struct odhcp6c_request_prefix);
ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
for (size_t i = 0; i < n_prefixes; i++) {
struct dhcpv6_ia_hdr hdr_ia_pd = {
htons(DHCPV6_OPT_IA_PD),
htons(sizeof(hdr_ia_pd) - 4 +
sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
request_prefixes[i].iaid, 0, 0
};
struct dhcpv6_ia_prefix pref = {
.type = htons(DHCPV6_OPT_IA_PREFIX),
.len = htons(sizeof(pref) - 4),
.prefix = request_prefixes[i].length
};
memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
ia_pd_len += sizeof(hdr_ia_pd);
if (request_prefixes[i].length) {
memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
ia_pd_len += sizeof(pref);
}
}
} else {
struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
ia_pd_entries /= sizeof(*e);
// we're too lazy to count our distinct IAIDs,
// so just allocate maximally needed space
ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
sizeof(struct dhcpv6_ia_hdr)));
for (size_t i = 0; i < ia_pd_entries; ++i) {
uint32_t iaid = e[i].iaid;
// check if this is an unprocessed IAID and skip if not.
int new_iaid = 1;
for (int j = i-1; j >= 0; j--) {
if (e[j].iaid == iaid) {
new_iaid = 0;
break;
}
}
if (!new_iaid)
continue;
// construct header
struct dhcpv6_ia_hdr hdr_ia_pd = {
htons(DHCPV6_OPT_IA_PD),
htons(sizeof(hdr_ia_pd) - 4),
iaid, 0, 0
};
memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
ia_pd_len += sizeof(hdr_ia_pd);
for (size_t j = i; j < ia_pd_entries; j++) {
if (e[j].iaid != iaid)
continue;
uint8_t ex_len = 0;
if (e[j].priority > 0)
ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
struct dhcpv6_ia_prefix p = {
.type = htons(DHCPV6_OPT_IA_PREFIX),
.len = htons(sizeof(p) - 4U + ex_len),
.prefix = e[j].length,
.addr = e[j].target
};
if (type == DHCPV6_MSG_REQUEST) {
p.preferred = htonl(e[j].preferred);
p.valid = htonl(e[j].valid);
}
memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
ia_pd_len += sizeof(p);
if (ex_len) {
ia_pd[ia_pd_len++] = 0;
ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
ia_pd[ia_pd_len++] = 0;
ia_pd[ia_pd_len++] = ex_len - 4;
ia_pd[ia_pd_len++] = e[j].priority;
uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
excl >>= (64 - e[j].priority);
excl <<= 8 - ((e[j].priority - e[j].length) % 8);
for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
ia_pd[ia_pd_len + i] = excl & 0xff;
ia_pd_len += ex_len - 5;
}
hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
}
}
}
if (ia_pd_entries > 0)
request_prefix = 1;
// Build IA_NAs
size_t ia_na_entries, ia_na_len = 0;
void *ia_na = NULL;
struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
ia_na_entries /= sizeof(*e);
struct dhcpv6_ia_hdr hdr_ia_na = {
htons(DHCPV6_OPT_IA_NA),
htons(sizeof(hdr_ia_na) - 4),
htonl(1), 0, 0
};
struct dhcpv6_ia_addr pa[ia_na_entries];
for (size_t i = 0; i < ia_na_entries; ++i) {
pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
pa[i].len = htons(sizeof(pa[i]) - 4U);
pa[i].addr = e[i].target;
if (type == DHCPV6_MSG_REQUEST) {
pa[i].preferred = htonl(e[i].preferred);
pa[i].valid = htonl(e[i].valid);
} else {
pa[i].preferred = 0;
pa[i].valid = 0;
}
}
ia_na = pa;
ia_na_len = sizeof(pa);
hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
// Reconfigure Accept
struct {
uint16_t type;
uint16_t length;
} reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
// Request Information Refresh
uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
// Build vendor-class option
size_t vendor_class_len, user_class_len;
struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
struct {
uint16_t type;
uint16_t length;
} vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
struct {
uint16_t type;
uint16_t length;
} user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
// Prepare Header
size_t oro_len;
void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
struct {
uint8_t type;
uint8_t trid[3];
uint16_t elapsed_type;
uint16_t elapsed_len;
uint16_t elapsed_value;
uint16_t oro_type;
uint16_t oro_len;
} hdr = {
type, {trid[0], trid[1], trid[2]},
htons(DHCPV6_OPT_ELAPSED), htons(2),
htons((ecs > 0xffff) ? 0xffff : ecs),
htons(DHCPV6_OPT_ORO), htons(oro_len),
};
struct iovec iov[IOV_TOTAL] = {
[IOV_HDR] = {&hdr, sizeof(hdr)},
[IOV_ORO] = {oro, oro_len},
[IOV_ORO_REFRESH] = {&oro_refresh, 0},
[IOV_CL_ID] = {cl_id, cl_id_len},
[IOV_SRV_ID] = {srv_id, srv_id_len},
[IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
[IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
[IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
[IOV_USER_CLASS] = {user_class, user_class_len},
[IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
[IOV_FQDN] = {&fqdn, fqdn_len},
[IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
[IOV_IA_NA] = {ia_na, ia_na_len},
[IOV_IA_PD] = {ia_pd, ia_pd_len},
};
size_t cnt = IOV_TOTAL;
if (type == DHCPV6_MSG_INFO_REQ) {
cnt = 9;
iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
} else if (!request_prefix) {
cnt = 13;
}
// Disable IAs if not used
if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
iov[IOV_HDR_IA_NA].iov_len = 0;
if (na_mode == IA_MODE_NONE)
iov[IOV_HDR_IA_NA].iov_len = 0;
if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
!(client_options & DHCPV6_ACCEPT_RECONFIGURE))
iov[IOV_RECONF_ACCEPT].iov_len = 0;
if (!(client_options & DHCPV6_CLIENT_FQDN))
iov[IOV_FQDN].iov_len = 0;
struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
0, ALL_DHCPV6_RELAYS, ifindex};
struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
.msg_iov = iov, .msg_iovlen = cnt};
sendmsg(sock, &msg, 0);
}
static int64_t dhcpv6_rand_delay(int64_t time)
{
int random;
odhcp6c_random(&random, sizeof(random));
return (time * ((int64_t)random % 1000LL)) / 10000LL;
}
int dhcpv6_request(enum dhcpv6_msg type)
{
uint8_t rc = 0;
uint64_t timeout = UINT32_MAX;
struct dhcpv6_retx *retx = &dhcpv6_retx[type];
if (retx->delay) {
struct timespec ts = {0, 0};
ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
}
if (type == DHCPV6_MSG_UNKNOWN)
timeout = t1;
else if (type == DHCPV6_MSG_RENEW)
timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
else if (type == DHCPV6_MSG_REBIND)
timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
if (timeout == 0)
return -1;
syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
retx->name, (unsigned long long)timeout, retx->max_rc);
uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
// Generate transaction ID
uint8_t trid[3] = {0, 0, 0};
if (type != DHCPV6_MSG_UNKNOWN)
odhcp6c_random(trid, sizeof(trid));
ssize_t len = -1;
int64_t rto = 0;
do {
if (rto == 0) {
int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
// First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
rto = (retx->init_timeo * 1000 + delay);
}
else
rto = (2 * rto + dhcpv6_rand_delay(rto));
if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
rto = retx->max_timeo * 1000 +
dhcpv6_rand_delay(retx->max_timeo * 1000);
// Calculate end for this round and elapsed time
uint64_t round_end = round_start + rto;
elapsed = round_start - start;
// Don't wait too long if timeout differs from infinite
if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
round_end = timeout * 1000 + start;
// Built and send package
switch (type) {
case DHCPV6_MSG_UNKNOWN:
break;
default:
syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
retx->name, (unsigned long long)elapsed, rc);
// Fall through
case DHCPV6_MSG_SOLICIT:
case DHCPV6_MSG_INFO_REQ:
dhcpv6_send(type, trid, elapsed / 10);
rc++;
}
// Receive rounds
for (; len < 0 && (round_start < round_end);
round_start = odhcp6c_get_milli_time()) {
uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
struct iovec iov = {buf, sizeof(buf)};
struct sockaddr_in6 addr;
struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
.msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf,
.msg_controllen = sizeof(cmsg_buf)};
struct in6_pktinfo *pktinfo = NULL;
// Check for pending signal
if (odhcp6c_signal_process())
return -1;
// Set timeout for receiving
uint64_t t = round_end - round_start;
struct timeval tv = {t / 1000, (t % 1000) * 1000};
setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
&tv, sizeof(tv));
// Receive cycle
len = recvmsg(sock, &msg, 0);
if (len < 0)
continue;
for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
ch = CMSG_NXTHDR(&msg, ch)) {
if (ch->cmsg_level == SOL_IPV6 &&
ch->cmsg_type == IPV6_PKTINFO) {
pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
break;
}
}
if (pktinfo == NULL) {
len = -1;
continue;
}
if (!dhcpv6_response_is_valid(buf, len, trid,
type, &pktinfo->ipi6_addr)) {
len = -1;
continue;
}
uint8_t *opt = &buf[4];
uint8_t *opt_end = opt + len - 4;
round_start = odhcp6c_get_milli_time();
elapsed = round_start - start;
syslog(LOG_NOTICE, "Got a valid reply after "
"%llums", (unsigned long long)elapsed);
if (retx->handler_reply)
len = retx->handler_reply(type, rc, opt, opt_end, &addr);
if (len > 0 && round_end - round_start > 1000)
round_end = 1000 + round_start;
}
// Allow
if (retx->handler_finish)
len = retx->handler_finish();
} while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
(!retx->max_rc || rc < retx->max_rc));
return len;
}
// Message validation checks according to RFC3315 chapter 15
static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
const uint8_t transaction[3], enum dhcpv6_msg type,
const struct in6_addr *daddr)
{
const struct dhcpv6_header *rep = buf;
if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
transaction, sizeof(rep->tr_id)))
return false; // Invalid reply
if (type == DHCPV6_MSG_SOLICIT) {
if (rep->msg_type != DHCPV6_MSG_ADVERT &&
rep->msg_type != DHCPV6_MSG_REPLY)
return false;
} else if (type == DHCPV6_MSG_UNKNOWN) {
if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
return false;
} else if (rep->msg_type != DHCPV6_MSG_REPLY) {
return false;
}
uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
rcmsg = DHCPV6_MSG_UNKNOWN;
uint16_t otype, olen = UINT16_MAX;
bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
ia_present = false, options_valid = true;
size_t client_id_len, server_id_len;
void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
if (otype == DHCPV6_OPT_CLIENTID) {
clientid_ok = (olen + 4U == client_id_len) && !memcmp(
&odata[-4], client_id, client_id_len);
} else if (otype == DHCPV6_OPT_SERVERID) {
if (server_id_len)
serverid_ok = (olen + 4U == server_id_len) && !memcmp(
&odata[-4], server_id, server_id_len);
else
serverid_ok = true;
} else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
sizeof(struct dhcpv6_auth_reconfigure)) {
struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
continue;
md5_ctx_t md5;
uint8_t serverhash[16], secretbytes[64], hash[16];
memcpy(serverhash, r->key, sizeof(serverhash));
memset(r->key, 0, sizeof(r->key));
memset(secretbytes, 0, sizeof(secretbytes));
memcpy(secretbytes, reconf_key, sizeof(reconf_key));
for (size_t i = 0; i < sizeof(secretbytes); ++i)
secretbytes[i] ^= 0x36;
md5_begin(&md5);
md5_hash(secretbytes, sizeof(secretbytes), &md5);
md5_hash(buf, len, &md5);
md5_end(hash, &md5);
for (size_t i = 0; i < sizeof(secretbytes); ++i) {
secretbytes[i] ^= 0x36;
secretbytes[i] ^= 0x5c;
}
md5_begin(&md5);
md5_hash(secretbytes, sizeof(secretbytes), &md5);
md5_hash(hash, 16, &md5);
md5_end(hash, &md5);
rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
} else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
rcmsg = odata[0];
} else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
ia_present = true;
if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
options_valid = false;
}
else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
(otype == DHCPV6_OPT_PD_EXCLUDE)) {
// Options are not allowed on global level
options_valid = false;
}
}
if (!options_valid || ((odata + olen) > end))
return false;
if (type == DHCPV6_MSG_INFO_REQ && ia_present)
return false;
if (rep->msg_type == DHCPV6_MSG_RECONF) {
if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
(rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
!rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
return false;
}
return clientid_ok && serverid_ok;
}
int dhcpv6_poll_reconfigure(void)
{
int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
if (ret != -1)
ret = dhcpv6_request(ret);
return ret;
}
static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
{
uint16_t otype, olen;
uint8_t *odata, msg = DHCPV6_MSG_RENEW;
dhcpv6_for_each_option(opt, end, otype, olen, odata)
if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
odata[0] == DHCPV6_MSG_RENEW ||
odata[0] == DHCPV6_MSG_INFO_REQ))
msg = odata[0];
dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
return msg;
}
// Collect all advertised servers
static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
{
uint16_t olen, otype;
uint8_t *odata, pref = 0;
struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
DHCPV6_SOL_MAX_RT,
DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
bool have_na = false;
int have_pd = 0;
dhcpv6_for_each_option(opt, end, otype, olen, odata) {
if (orig == DHCPV6_MSG_SOLICIT &&
(otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
}
if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
memcpy(cand.duid, odata, olen);
cand.duid_len = olen;
} else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
cand.preference >= 0) {
cand.preference = pref = odata[0];
} else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
cand.wants_reconfigure = true;
} else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
cand.sol_max_rt = sol_max_rt;
} else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
cand.inf_max_rt = inf_max_rt;
} else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
uint8_t *oend = odata + olen, *d;
dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
if (otype == DHCPV6_OPT_IA_PREFIX &&
olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
have_pd = p->prefix;
}
}
} else if (otype == DHCPV6_OPT_IA_NA &&
olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
uint8_t *oend = odata + olen, *d;
dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
if (otype == DHCPV6_OPT_IA_ADDR &&
olen >= -4 + sizeof(struct dhcpv6_ia_addr))
have_na = true;
}
}
if ((!have_na && na_mode == IA_MODE_FORCE) ||
(!have_pd && pd_mode == IA_MODE_FORCE)) {
/*
* RFC7083 states to process the SOL_MAX_RT and
* INF_MAX_RT options even if the DHCPv6 server
* did not propose any IA_NA and/or IA_PD
*/
dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
return -1;
}
if (na_mode != IA_MODE_NONE && !have_na) {
cand.has_noaddravail = true;
cand.preference -= 1000;
}
if (pd_mode != IA_MODE_NONE) {
if (have_pd)
cand.preference += 2000 + (128 - have_pd);
else
cand.preference -= 2000;
}
if (cand.duid_len > 0) {
cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
dhcpv6_add_server_cand(&cand);
}
return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
}
static int dhcpv6_commit_advert(void)
{
return dhcpv6_promote_server_cand();
}
static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
const void *opt, const void *end, const struct sockaddr_in6 *from)
{
dhcpv6_handle_advert(orig, rc, opt, end, from);
if (dhcpv6_commit_advert() < 0)
return -1;
return dhcpv6_handle_reply(orig, rc, opt, end, from);
}
static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
const void *opt, const void *end, const struct sockaddr_in6 *from)
{
uint8_t *odata;
uint16_t otype, olen;
uint32_t refresh = 86400;
int ret = 1;
bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
odhcp6c_expire();
if (orig == DHCPV6_MSG_UNKNOWN) {
static time_t last_update = 0;
time_t now = odhcp6c_get_milli_time() / 1000;
uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
last_update = now;
if (t1 != UINT32_MAX)
t1 -= elapsed;
if (t2 != UINT32_MAX)
t2 -= elapsed;
if (t3 != UINT32_MAX)
t3 -= elapsed;
if (t1 < 0)
t1 = 0;
if (t2 < 0)
t2 = 0;
if (t3 < 0)
t3 = 0;
}
if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
// Delete NA and PD we have in the state from the Advert
odhcp6c_clear_state(STATE_IA_NA);
odhcp6c_clear_state(STATE_IA_PD);
}
if (opt) {
odhcp6c_clear_state(STATE_DNS);
odhcp6c_clear_state(STATE_SEARCH);
odhcp6c_clear_state(STATE_SNTP_IP);
odhcp6c_clear_state(STATE_NTP_IP);
odhcp6c_clear_state(STATE_NTP_FQDN);
odhcp6c_clear_state(STATE_SIP_IP);
odhcp6c_clear_state(STATE_SIP_FQDN);
odhcp6c_clear_state(STATE_AFTR_NAME);
odhcp6c_clear_state(STATE_CER);
odhcp6c_clear_state(STATE_S46_MAPT);
odhcp6c_clear_state(STATE_S46_MAPE);
odhcp6c_clear_state(STATE_S46_LW);
odhcp6c_clear_state(STATE_PASSTHRU);
odhcp6c_clear_state(STATE_CUSTOM_OPTS);
// Parse and find all matching IAs
dhcpv6_for_each_option(opt, end, otype, olen, odata) {
bool passthru = true;
if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
&& olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
(pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
continue;
// Test ID
if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
continue;
uint16_t code = DHCPV6_Success;
uint16_t stype, slen;
uint8_t *sdata;
// Get and handle status code
dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
stype, slen, sdata) {
if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
uint16_t mlen = (slen > 2) ? slen - 2 : 0;
code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
if (code == DHCPV6_Success)
continue;
dhcpv6_handle_ia_status_code(orig, ia_hdr,
code, mdata, mlen, handled_status_codes, &ret);
if (ret > 0)
return ret;
break;
}
}
if (code != DHCPV6_Success)
continue;
dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
passthru = false;
} else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
uint16_t mlen = (olen > 2) ? olen - 2 : 0;
uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
passthru = false;