diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/dhcpv4.c | 18 | ||||
| -rw-r--r-- | src/dhcpv4.h | 3 |
2 files changed, 16 insertions, 5 deletions
diff --git a/src/dhcpv4.c b/src/dhcpv4.c index 7058b83..3fb5988 100644 --- a/src/dhcpv4.c +++ b/src/dhcpv4.c @@ -35,6 +35,9 @@ #include "dhcpv4.h" #include "dhcpv6.h" +#define PACKET_SIZE(start, end) (((uint8_t *)end - (uint8_t *)start) < DHCPV4_MIN_PACKET_SIZE ? \ + DHCPV4_MIN_PACKET_SIZE : (uint8_t *)end - (uint8_t *)start) + static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info); static int setup_dhcpv4_addresses(struct interface *iface); static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr); @@ -429,15 +432,20 @@ static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie, { uint8_t *c = *cookie; uint8_t *end = (uint8_t *)msg + sizeof(*msg); + bool tag_only = type == DHCPV4_OPT_PAD || type == DHCPV4_OPT_END; + int total_len = tag_only ? 1 : 2 + len; - if (*cookie + 2 + len > end) + if (*cookie + total_len > end) return; + *cookie += total_len; *c++ = type; + + if (tag_only) + return; + *c++ = len; memcpy(c, data, len); - - *cookie = c + len; } static void dhcpv4_fr_send(struct dhcp_assignment *a) @@ -518,7 +526,7 @@ static void dhcpv4_fr_send(struct dhcp_assignment *a) dest.sin_port = htons(DHCPV4_CLIENT_PORT); dest.sin_addr.s_addr = a->addr; - if (sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, sizeof(fr_msg), + if (sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, PACKET_SIZE(&fr_msg, cookie), MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0) syslog(LOG_ERR, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg), odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr)); @@ -861,7 +869,7 @@ static void handle_dhcpv4(void *addr, void *data, size_t len, syslog(LOG_ERR, "ioctl(SIOCSARP): %m"); } - if (sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT, + if (sendto(sock, &reply, PACKET_SIZE(&reply, cookie), MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0) syslog(LOG_ERR, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg), diff --git a/src/dhcpv4.h b/src/dhcpv4.h index 96bd068..505346f 100644 --- a/src/dhcpv4.h +++ b/src/dhcpv4.h @@ -19,6 +19,8 @@ #define DHCPV4_FLAG_BROADCAST 0x8000 +#define DHCPV4_MIN_PACKET_SIZE 300 + enum dhcpv4_op { DHCPV4_BOOTREQUEST = 1, DHCPV4_BOOTREPLY = 2 @@ -37,6 +39,7 @@ enum dhcpv4_msg { }; enum dhcpv4_opt { + DHCPV4_OPT_PAD = 0, DHCPV4_OPT_NETMASK = 1, DHCPV4_OPT_ROUTER = 3, DHCPV4_OPT_DNSSERVER = 6, |