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https://github.com/sheumann/hush.git
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5d61e71c3a
function old new delta safe_poll - 77 +77 svlogd_main 1470 1466 -4 zcip_main 1530 1524 -6 forkexec 1345 1338 -7 decode_format_string 795 788 -7 collect_blk 474 467 -7 buffer_pread 540 532 -8 tftp 1182 1172 -10 microcom_main 763 749 -14 arpping 441 424 -17 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 0/9 up/down: 77/-80) Total: -3 bytes text data bss dec hex filename 770162 1034 10404 781600 bed20 busybox_old 770158 1034 10404 781596 bed1c busybox_unstripped
106 lines
3.3 KiB
C
106 lines
3.3 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* arpping.c
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*
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* Mostly stolen from: dhcpcd - DHCP client daemon
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* by Yoichi Hariguchi <yoichi@fore.com>
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*/
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#include <netinet/if_ether.h>
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#include <net/if_arp.h>
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#include "common.h"
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#include "dhcpd.h"
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struct arpMsg {
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/* Ethernet header */
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uint8_t h_dest[6]; /* 00 destination ether addr */
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uint8_t h_source[6]; /* 06 source ether addr */
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uint16_t h_proto; /* 0c packet type ID field */
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/* ARP packet */
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uint16_t htype; /* 0e hardware type (must be ARPHRD_ETHER) */
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uint16_t ptype; /* 10 protocol type (must be ETH_P_IP) */
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uint8_t hlen; /* 12 hardware address length (must be 6) */
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uint8_t plen; /* 13 protocol address length (must be 4) */
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uint16_t operation; /* 14 ARP opcode */
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uint8_t sHaddr[6]; /* 16 sender's hardware address */
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uint8_t sInaddr[4]; /* 1c sender's IP address */
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uint8_t tHaddr[6]; /* 20 target's hardware address */
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uint8_t tInaddr[4]; /* 26 target's IP address */
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uint8_t pad[18]; /* 2a pad for min. ethernet payload (60 bytes) */
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} ATTRIBUTE_PACKED;
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/* Returns 1 if no reply received */
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int arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *interface)
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{
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int timeout_ms = 2000;
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struct pollfd pfd[1];
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#define s (pfd[0].fd) /* socket */
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int rv = 1; /* "no reply received" yet */
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struct sockaddr addr; /* for interface name */
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struct arpMsg arp;
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s = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP));
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if (s == -1) {
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bb_perror_msg(bb_msg_can_not_create_raw_socket);
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return -1;
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}
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if (setsockopt_broadcast(s) == -1) {
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bb_perror_msg("cannot setsocketopt on raw socket");
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goto ret;
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}
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/* send arp request */
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memset(&arp, 0, sizeof(arp));
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memset(arp.h_dest, 0xff, 6); /* MAC DA */
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memcpy(arp.h_source, from_mac, 6); /* MAC SA */
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arp.h_proto = htons(ETH_P_ARP); /* protocol type (Ethernet) */
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arp.htype = htons(ARPHRD_ETHER); /* hardware type */
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arp.ptype = htons(ETH_P_IP); /* protocol type (ARP message) */
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arp.hlen = 6; /* hardware address length */
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arp.plen = 4; /* protocol address length */
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arp.operation = htons(ARPOP_REQUEST); /* ARP op code */
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memcpy(arp.sHaddr, from_mac, 6); /* source hardware address */
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memcpy(arp.sInaddr, &from_ip, sizeof(from_ip)); /* source IP address */
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/* tHaddr */ /* target hardware address */
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memcpy(arp.tInaddr, &test_ip, sizeof(test_ip)); /* target IP address */
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memset(&addr, 0, sizeof(addr));
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safe_strncpy(addr.sa_data, interface, sizeof(addr.sa_data));
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if (sendto(s, &arp, sizeof(arp), 0, &addr, sizeof(addr)) < 0)
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goto ret;
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/* wait for arp reply, and check it */
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do {
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int r;
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unsigned prevTime = monotonic_us();
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pfd[0].events = POLLIN;
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r = safe_poll(pfd, 1, timeout_ms);
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if (r < 0) {
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break;
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} else if (r) {
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if (read(s, &arp, sizeof(arp)) < 0)
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break;
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if (arp.operation == htons(ARPOP_REPLY)
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&& memcmp(arp.tHaddr, from_mac, 6) == 0
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&& *((uint32_t *) arp.sInaddr) == test_ip
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) {
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rv = 0;
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break;
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}
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}
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timeout_ms -= (monotonic_us() - prevTime) / 1000;
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} while (timeout_ms > 0);
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ret:
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close(s);
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DEBUG("%srp reply received for this address", rv ? "No a" : "A");
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return rv;
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}
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