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Add error checking to handle renew failure #93

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Add error checking to handle renew failure #93

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78 changes: 45 additions & 33 deletions src/dhcpv6.c
View file
Original file line number Diff line number Diff line change
@@ -59,7 +59,7 @@ 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 unsigned int dhcpv6_parse_ia(void *opt, void *end);
static unsigned int dhcpv6_parse_ia(void *opt, void *end, int *ret);

static unsigned int dhcpv6_calc_refresh_timers(void);
static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
@@ -73,6 +73,9 @@ static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
static void dhcpv6_clear_all_server_cand(void);

static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
const void *status_msg, int len);

static reply_handler dhcpv6_handle_reply;
static reply_handler dhcpv6_handle_advert;
static reply_handler dhcpv6_handle_rebind_reply;
@@ -959,7 +962,7 @@ static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
(otype == DHCPV6_OPT_IA_NA && na_mode != IA_MODE_NONE)) &&
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));
dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr), NULL);
}

if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
@@ -1164,7 +1167,7 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
if (code != DHCPV6_Success)
continue;

updated_IAs += dhcpv6_parse_ia(ia_hdr, odata + olen);
updated_IAs += dhcpv6_parse_ia(ia_hdr, odata + olen, &ret);
} else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
server_addr = *(struct in6_addr *)odata;
@@ -1338,7 +1341,7 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
return ret;
}

static unsigned int dhcpv6_parse_ia(void *opt, void *end)
static unsigned int dhcpv6_parse_ia(void *opt, void *end, int *ret)
{
struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
unsigned int updated_IAs = 0;
@@ -1383,43 +1386,52 @@ static unsigned int dhcpv6_parse_ia(void *opt, void *end)
uint16_t stype, slen;
uint8_t *sdata;

// Parse PD-exclude
bool ok = true;
// Parse sub-options for PD-exclude or error status code
bool update_state = true;
dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
odata + olen, stype, slen, sdata) {
if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
continue;

uint8_t elen = sdata[0];
if (elen > 64)
elen = 64;

if (entry.length < 32 || elen <= entry.length) {
ok = false;
continue;
}
if (stype == DHCPV6_OPT_STATUS && slen > 2) {
uint8_t *status_msg = (slen > 2) ? &sdata[2] : NULL;
uint16_t msg_len = (slen > 2) ? slen - 2 : 0;
uint16_t code = ((int)sdata[0]) << 8 | ((int)sdata[1]);

if (code == DHCPV6_Success)
continue;

dhcpv6_log_status_code(code, "IA_PREFIX", status_msg, msg_len);
if (ret) *ret = 0; // renewal failed
} else if (stype == DHCPV6_OPT_PD_EXCLUDE && slen > 2) {
uint8_t elen = sdata[0];
if (elen > 64)
elen = 64;

if (entry.length < 32 || elen <= entry.length) {
update_state = false;
continue;
}

uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
if (slen <= bytes) {
ok = false;
continue;
}
uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
if (slen <= bytes) {
update_state = false;
continue;
}

uint32_t exclude = 0;
do {
exclude = exclude << 8 | sdata[bytes];
} while (--bytes);
uint32_t exclude = 0;
do {
exclude = exclude << 8 | sdata[bytes];
} while (--bytes);

exclude >>= 8 - ((elen - entry.length) % 8);
exclude <<= 64 - elen;
exclude >>= 8 - ((elen - entry.length) % 8);
exclude <<= 64 - elen;

// Abusing router & priority fields for exclusion
entry.router = entry.target;
entry.router.s6_addr32[1] |= htonl(exclude);
entry.priority = elen;
// Abusing router & priority fields for exclusion
entry.router = entry.target;
entry.router.s6_addr32[1] |= htonl(exclude);
entry.priority = elen;
}
}

if (ok) {
if (update_state) {
if (odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0))
updated_IAs++;

3 changes: 3 additions & 0 deletions src/odhcp6c.c
View file
Original file line number Diff line number Diff line change
@@ -573,6 +573,9 @@ int main(_unused int argc, char* const argv[])
odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
odhcp6c_clear_state(STATE_SERVER_ADDR);

// Remove any state invalidated by RENEW reply
odhcp6c_expire(true);

size_t ia_pd_len, ia_na_len;
odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
odhcp6c_get_state(STATE_IA_NA, &ia_na_len);