diff options
| -rw-r--r-- | networking/udhcp/dhcpc.c | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index 25f18b35d..7dfc160e2 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -1232,7 +1232,7 @@ static void client_background(void) int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int udhcpc_main(int argc UNUSED_PARAM, char **argv) { - uint8_t *temp, *message; + uint8_t *message; const char *str_V, *str_h, *str_F, *str_r; IF_FEATURE_UDHCP_PORT(char *str_P;) void *clientid_mac_ptr; @@ -1640,6 +1640,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) case INIT_SELECTING: /* Must be a DHCPOFFER */ if (*message == DHCPOFFER) { + uint8_t *temp; + /* What exactly is server's IP? There are several values. * Example DHCP offer captured with tchdump: * @@ -1689,6 +1691,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) if (*message == DHCPACK) { uint32_t lease_seconds; struct in_addr temp_addr; + uint8_t *temp; temp = udhcp_get_option(&packet, DHCP_LEASE_TIME); if (!temp) { @@ -1766,6 +1769,26 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) continue; /* back to main loop */ } if (*message == DHCPNAK) { + /* If network has more than one DHCP server, + * "wrong" server can reply first, with a NAK. + * Do not interpret it as a NAK from "our" server. + */ + if (server_addr != 0) { + uint32_t svid; + uint8_t *temp; + + temp = udhcp_get_option(&packet, DHCP_SERVER_ID); + if (!temp) { + non_matching_svid: + log1("%s with wrong server ID, ignoring packet", + "Received DHCP NAK" + ); + continue; + } + move_from_unaligned32(svid, temp); + if (svid != server_addr) + goto non_matching_svid; + } /* return to init state */ bb_info_msg("Received DHCP NAK"); udhcp_run_script(&packet, "nak"); |