d72b24a2fe
Handle EAGAIN and EWOULDBLOCK more gracefully when dealing with safe_read(). All occurrences of safe_read() should only be invoked on fds that have signaled ready-to-read state via the epoll() mechanism, so this change should not result in any observable difference, but it is best to be safe. Additionally, a constant stack variable is converted to an equivalent macro define for cleanliness. Finally, print the error type encountered if reading data from an ARP response fails with a read error.
79 lines
3.0 KiB
C
79 lines
3.0 KiB
C
/* packet.h - send and react to DHCP message packets
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* Time-stamp: <2011-03-30 23:57:02 nk>
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*
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* (c) 2004-2011 Nicholas J. Kain <njkain at gmail dot com>
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* (c) 2001 Russ Dill <Russ.Dill@asu.edu>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef PACKET_H_
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#define PACKET_H_
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#include <netinet/udp.h>
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#include <netinet/ip.h>
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#include "config.h"
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struct dhcpMessage {
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uint8_t op; // Message type: 1 = BOOTREQUEST for clients.
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uint8_t htype; // ARP HW address type: always '1' for 10MB ethernet.
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uint8_t hlen; // Hardware address length: always '6' for 10MB ethernet.
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uint8_t hops; // Client sets to zero.
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uint32_t xid; // Transaction ID: random number identifying session
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uint16_t secs; // Filled by client: seconds since client began address
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// aquisition or renewal process.
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uint16_t flags; // DHCP flags
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uint32_t ciaddr; // Client IP: only filled in if client is inBOUND, RENEW,
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// or REBINDING and can reply to ARP requests
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uint32_t yiaddr; // 'your' (client) IP address
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uint32_t siaddr; // IP address of next server to use in bootstrap; returned
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// in DHCPOFFER or DHCPACK by server
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uint32_t giaddr; // relay agent IP: used when booting via relay agent
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uint8_t chaddr[16]; // Client MAC address
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uint8_t sname[64]; // Server host name (optional); null-terminated string
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uint8_t file[128]; // boot file name, null-terminated string
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uint32_t cookie;
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uint8_t options[308]; /* 312 - cookie */
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};
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struct ip_udp_dhcp_packet {
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struct iphdr ip;
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struct udphdr udp;
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struct dhcpMessage data;
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};
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struct udp_dhcp_packet {
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struct udphdr udp;
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struct dhcpMessage data;
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};
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enum {
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IP_UPD_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet),
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UPD_DHCP_SIZE = sizeof(struct udp_dhcp_packet),
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DHCP_SIZE = sizeof(struct dhcpMessage),
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};
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int get_packet(struct dhcpMessage *packet, int fd);
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uint16_t checksum(void *addr, int count);
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int raw_packet(struct dhcpMessage *payload, uint32_t source_ip,
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int source_port, uint32_t dest_ip, int dest_port,
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uint8_t *dest_arp, int ifindex);
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int kernel_packet(struct dhcpMessage *payload, uint32_t source_ip,
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int source_port, uint32_t dest_ip, int dest_port);
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void change_listen_mode(struct client_state_t *cs, int new_mode);
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void handle_packet(struct client_state_t *cs);
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#endif
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