| /* |
| * ipconfig/dhcp_proto.c |
| * |
| * DHCP RFC 2131 and 2132 |
| */ |
| #include <sys/types.h> |
| #include <sys/uio.h> |
| #include <netinet/in.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <time.h> |
| |
| #include "ipconfig.h" |
| #include "netdev.h" |
| #include "bootp_packet.h" |
| #include "bootp_proto.h" |
| #include "dhcp_proto.h" |
| #include "packet.h" |
| |
| static __u8 dhcp_params[] = { |
| 1, /* subnet mask */ |
| 3, /* default gateway */ |
| 6, /* DNS server */ |
| 12, /* host name */ |
| 15, /* domain name */ |
| 17, /* boot path */ |
| 28, /* broadcast addr */ |
| 40, /* NIS domain name */ |
| }; |
| |
| static __u8 dhcp_discover_hdr[] = { |
| 99, 130, 83, 99, /* bootp cookie */ |
| 53, 1, DHCPDISCOVER, /* dhcp message type */ |
| 55, sizeof(dhcp_params),/* parameter list */ |
| }; |
| |
| static __u8 dhcp_request_hdr[] = { |
| 99, 130, 83, 99, /* boot cookie */ |
| 53, 1, DHCPREQUEST, /* dhcp message type */ |
| #define SERVER_IP_OFF 9 |
| 54, 4, 0, 0, 0, 0, /* server IP */ |
| #define REQ_IP_OFF 15 |
| 50, 4, 0, 0, 0, 0, /* requested IP address */ |
| 55, sizeof(dhcp_params),/* parameter list */ |
| }; |
| |
| static __u8 dhcp_end[] = { |
| 255, |
| }; |
| |
| static struct iovec dhcp_discover_iov[] = { |
| /* [0] = ip + udp header */ |
| /* [1] = bootp header */ |
| [2] = { dhcp_discover_hdr, sizeof(dhcp_discover_hdr) }, |
| [3] = { dhcp_params, sizeof(dhcp_params) }, |
| [4] = { dhcp_end, sizeof(dhcp_end) } |
| }; |
| |
| static struct iovec dhcp_request_iov[] = { |
| /* [0] = ip + udp header */ |
| /* [1] = bootp header */ |
| [2] = { dhcp_request_hdr, sizeof(dhcp_request_hdr) }, |
| [3] = { dhcp_params, sizeof(dhcp_params) }, |
| [4] = { dhcp_end, sizeof(dhcp_end) } |
| }; |
| |
| /* |
| * Parse a DHCP response packet |
| */ |
| static int |
| dhcp_parse(struct netdev *dev, struct bootp_hdr *hdr, __u8 *exts, int extlen) |
| { |
| __u8 type = 0; |
| __u32 serverid = INADDR_NONE; |
| int ret = 0; |
| |
| if (extlen >= 4 && exts[0] == 99 && exts[1] == 130 && |
| exts[2] == 83 && exts[3] == 99) { |
| __u8 *ext; |
| |
| for (ext = exts + 4; ext - exts < extlen; ) { |
| __u8 len, *opt = ext++; |
| if (*opt == 0) |
| continue; |
| |
| len = *ext++; |
| |
| ext += len; |
| |
| if (*opt == 53) |
| type = opt[2]; |
| if (*opt == 54) |
| memcpy(&serverid, opt + 2, 4); |
| } |
| } |
| |
| switch (type) { |
| case DHCPOFFER: |
| ret = bootp_parse(dev, hdr, exts, extlen); |
| if (ret == 1 && serverid != INADDR_NONE) |
| dev->serverid = serverid; |
| DEBUG(("\n dhcp offer\n")); |
| break; |
| |
| case DHCPACK: |
| ret = bootp_parse(dev, hdr, exts, extlen); |
| DEBUG(("\n dhcp ack\n")); |
| break; |
| |
| case DHCPNAK: |
| ret = 2; |
| DEBUG(("\n dhcp nak\n")); |
| break; |
| } |
| return ret; |
| } |
| |
| /* |
| * Receive and parse a DHCP packet |
| */ |
| static int dhcp_recv(struct netdev *dev) |
| { |
| struct bootp_hdr bootp; |
| __u8 dhcp_options[1500]; |
| struct iovec iov[] = { |
| /* [0] = ip + udp header */ |
| [1] = { &bootp, sizeof(struct bootp_hdr) }, |
| [2] = { dhcp_options, sizeof(dhcp_options) } |
| }; |
| int ret; |
| |
| ret = packet_recv(iov, 3); |
| if (ret <= 0) |
| return ret; |
| |
| DEBUG(("\n dhcp xid %08x ", dev->bootp.xid)); |
| |
| if (ret < sizeof(struct bootp_hdr) || |
| bootp.op != BOOTP_REPLY || /* RFC951 7.5 */ |
| bootp.xid != dev->bootp.xid || |
| memcmp(bootp.chaddr, dev->hwaddr, 16)) |
| return 0; |
| |
| ret -= sizeof(struct bootp_hdr); |
| |
| return dhcp_parse(dev, &bootp, dhcp_options, ret); |
| } |
| |
| static int dhcp_send(struct netdev *dev, struct iovec *vec, int len) |
| { |
| struct bootp_hdr bootp; |
| |
| memset(&bootp, 0, sizeof(struct bootp_hdr)); |
| |
| bootp.op = BOOTP_REQUEST; |
| bootp.htype = dev->hwtype; |
| bootp.hlen = dev->hwlen; |
| bootp.xid = dev->bootp.xid; |
| bootp.ciaddr = dev->ip_addr; |
| bootp.giaddr = dev->bootp.gateway; |
| bootp.secs = htons(time(NULL) - dev->open_time); |
| memcpy(bootp.chaddr, dev->hwaddr, 16); |
| |
| vec[1].iov_base = &bootp; |
| vec[1].iov_len = sizeof(struct bootp_hdr); |
| |
| DEBUG(("xid %08x secs %d ", |
| bootp.xid, ntohs(bootp.secs))); |
| |
| return packet_send(dev, vec, len); |
| } |
| |
| /* |
| * Send a DHCP discover packet |
| */ |
| int dhcp_send_discover(struct netdev *dev) |
| { |
| dev->ip_addr = INADDR_ANY; |
| dev->ip_gateway = INADDR_ANY; |
| |
| DEBUG(("-> dhcp discover ")); |
| |
| return dhcp_send(dev, dhcp_discover_iov, 5); |
| } |
| |
| /* |
| * Receive a DHCP offer packet |
| */ |
| int dhcp_recv_offer(struct netdev *dev) |
| { |
| return dhcp_recv(dev); |
| } |
| |
| /* |
| * Send a DHCP request packet |
| */ |
| int dhcp_send_request(struct netdev *dev) |
| { |
| memcpy(&dhcp_request_hdr[SERVER_IP_OFF], &dev->serverid, 4); |
| memcpy(&dhcp_request_hdr[REQ_IP_OFF], &dev->ip_addr, 4); |
| |
| DEBUG(("-> dhcp request ")); |
| |
| return dhcp_send(dev, dhcp_request_iov, 5); |
| } |
| |
| /* |
| * Receive a DHCP ack packet |
| */ |
| int dhcp_recv_ack(struct netdev *dev) |
| { |
| return dhcp_recv(dev); |
| } |