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-rw-r--r--avahi-autoipd/main.c344
1 files changed, 304 insertions, 40 deletions
diff --git a/avahi-autoipd/main.c b/avahi-autoipd/main.c
index 60fc8aa..58811a3 100644
--- a/avahi-autoipd/main.c
+++ b/avahi-autoipd/main.c
@@ -23,32 +23,49 @@
#include <config.h>
#endif
-#include <stdlib.h>
-#include <unistd.h>
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
#include <sys/socket.h>
+#include <sys/wait.h>
+#ifdef __FreeBSD__
+#include <sys/sysctl.h>
+#endif
+
+#ifdef __linux__
#include <netpacket/packet.h>
+#endif
#include <net/ethernet.h>
-#include <fcntl.h>
-#include <time.h>
+#include <net/if.h>
+#ifdef __FreeBSD__
+#include <net/if_dl.h>
+#include <net/route.h>
+#endif
+#include <arpa/inet.h>
+
#include <assert.h>
#include <errno.h>
-#include <string.h>
#include <inttypes.h>
-#include <sys/types.h>
-#include <arpa/inet.h>
-#include <sys/ioctl.h>
-#include <poll.h>
-#include <net/if.h>
+#include <fcntl.h>
+#include <stdlib.h>
#include <stdio.h>
-#include <getopt.h>
#include <signal.h>
-#include <sys/wait.h>
-#include <pwd.h>
+#include <string.h>
+#include <time.h>
+#include <getopt.h>
+
#include <grp.h>
+#include <poll.h>
+#include <pwd.h>
+#include <unistd.h>
+
+#ifndef __linux__
+#include <pcap.h>
+#endif
#include <avahi-common/malloc.h>
#include <avahi-common/timeval.h>
-
#include <avahi-daemon/setproctitle.h>
#include <libdaemon/dfork.h>
@@ -60,10 +77,6 @@
#include "main.h"
#include "iface.h"
-#ifndef __linux__
-#error "avahi-autoipd is only available on Linux for now"
-#endif
-
/* An implementation of RFC 3927 */
/* Constants from the RFC */
@@ -84,6 +97,7 @@
#define IPV4LL_BROADCAST 0xA9FEFFFFL
#define ETHER_ADDRLEN 6
+#define ETHER_HDR_SIZE (2+2*ETHER_ADDRLEN)
#define ARP_PACKET_SIZE (8+4+4+2*ETHER_ADDRLEN)
typedef enum ArpOperation {
@@ -98,6 +112,11 @@ typedef struct ArpPacketInfo {
uint8_t sender_hw_address[ETHER_ADDRLEN], target_hw_address[ETHER_ADDRLEN];
} ArpPacketInfo;
+typedef struct ArpPacket {
+ uint8_t *ether_header;
+ uint8_t *ether_payload;
+} ArpPacket;
+
static State state = STATE_START;
static int n_iteration = 0;
static int n_conflict = 0;
@@ -249,16 +268,44 @@ fail:
return -1;
}
-static void* packet_new(const ArpPacketInfo *info, size_t *packet_len) {
+/*
+ * Allocate a buffer with two pointers in front, one of which is
+ * guaranteed to point ETHER_HDR_SIZE bytes into it.
+ */
+static ArpPacket* packet_new(size_t packet_len) {
+ ArpPacket *p;
+ uint8_t *b;
+
+ assert(packet_len > 0);
+
+#ifdef __linux__
+ b = avahi_new0(uint8_t, sizeof(struct ArpPacket) + packet_len);
+ p = (ArpPacket*) b;
+ p->ether_header = NULL;
+ p->ether_payload = b + sizeof(struct ArpPacket);
+
+#else
+ b = avahi_new0(uint8_t, sizeof(struct ArpPacket) + ETHER_HDR_SIZE + packet_len);
+ p = (ArpPacket*) b;
+ p->ether_header = b + sizeof(struct ArpPacket);
+ p->ether_payload = b + sizeof(struct ArpPacket) + ETHER_HDR_SIZE;
+#endif
+
+ return p;
+}
+
+static ArpPacket* packet_new_with_info(const ArpPacketInfo *info, size_t *packet_len) {
+ ArpPacket *p = NULL;
uint8_t *r;
assert(info);
- assert(packet_len);
assert(info->operation == ARP_REQUEST || info->operation == ARP_RESPONSE);
+ assert(packet_len != NULL);
*packet_len = ARP_PACKET_SIZE;
- r = avahi_new0(uint8_t, *packet_len);
-
+ p = packet_new(*packet_len);
+ r = p->ether_payload;
+
r[1] = 1; /* HTYPE */
r[2] = 8; /* PTYPE */
r[4] = ETHER_ADDRLEN; /* HLEN */
@@ -270,10 +317,10 @@ static void* packet_new(const ArpPacketInfo *info, size_t *packet_len) {
memcpy(r+18, info->target_hw_address, ETHER_ADDRLEN);
memcpy(r+24, &info->target_ip_address, 4);
- return r;
+ return p;
}
-static void *packet_new_probe(uint32_t ip_address, const uint8_t*hw_address, size_t *packet_len) {
+static ArpPacket *packet_new_probe(uint32_t ip_address, const uint8_t*hw_address, size_t *packet_len) {
ArpPacketInfo info;
memset(&info, 0, sizeof(info));
@@ -281,10 +328,10 @@ static void *packet_new_probe(uint32_t ip_address, const uint8_t*hw_address, siz
memcpy(info.sender_hw_address, hw_address, ETHER_ADDRLEN);
info.target_ip_address = ip_address;
- return packet_new(&info, packet_len);
+ return packet_new_with_info(&info, packet_len);
}
-static void *packet_new_announcement(uint32_t ip_address, const uint8_t* hw_address, size_t *packet_len) {
+static ArpPacket *packet_new_announcement(uint32_t ip_address, const uint8_t* hw_address, size_t *packet_len) {
ArpPacketInfo info;
memset(&info, 0, sizeof(info));
@@ -293,13 +340,15 @@ static void *packet_new_announcement(uint32_t ip_address, const uint8_t* hw_addr
info.target_ip_address = ip_address;
info.sender_ip_address = ip_address;
- return packet_new(&info, packet_len);
+ return packet_new_with_info(&info, packet_len);
}
-static int packet_parse(const void *data, size_t packet_len, ArpPacketInfo *info) {
- const uint8_t *p = data;
+static int packet_parse(const ArpPacket *packet, size_t packet_len, ArpPacketInfo *info) {
+ const uint8_t *p;
- assert(data);
+ assert(packet);
+ p = (uint8_t *)packet->ether_payload;
+ assert(p);
if (packet_len < ARP_PACKET_SIZE)
return -1;
@@ -392,6 +441,10 @@ fail:
return -1;
}
+#ifdef __linux__
+
+/* Linux 'packet socket' specific implementation */
+
static int open_socket(int iface, uint8_t *hw_address) {
int fd = -1;
struct sockaddr_ll sa;
@@ -437,7 +490,7 @@ fail:
return -1;
}
-static int send_packet(int fd, int iface, void *packet, size_t packet_len) {
+static int send_packet(int fd, int iface, ArpPacket *packet, size_t packet_len) {
struct sockaddr_ll sa;
assert(fd >= 0);
@@ -459,7 +512,7 @@ static int send_packet(int fd, int iface, void *packet, size_t packet_len) {
return 0;
}
-static int recv_packet(int fd, void **packet, size_t *packet_len) {
+static int recv_packet(int fd, ArpPacket **packet, size_t *packet_len) {
int s;
struct sockaddr_ll sa;
socklen_t sa_len;
@@ -479,10 +532,10 @@ static int recv_packet(int fd, void **packet, size_t *packet_len) {
if (s <= 0)
s = 4096;
- *packet = avahi_new(uint8_t, s);
+ *packet = packet_new(s);
sa_len = sizeof(sa);
- if ((r = recvfrom(fd, *packet, s, 0, (struct sockaddr*) &sa, &sa_len)) < 0) {
+ if ((r = recvfrom(fd, (*packet)->ether_payload, s, 0, (struct sockaddr*) &sa, &sa_len)) < 0) {
daemon_log(LOG_ERR, "recvfrom() failed: %s", strerror(errno));
goto fail;
}
@@ -499,7 +552,214 @@ fail:
return -1;
}
-
+
+static void
+close_socket(int fd) {
+ close(fd);
+}
+
+#else /* !__linux__ */
+/* PCAP-based implementation */
+
+static pcap_t *__pp;
+static char __pcap_errbuf[PCAP_ERRBUF_SIZE];
+static uint8_t __lladdr[ETHER_ADDRLEN];
+
+#ifndef elementsof
+#define elementsof(array) (sizeof(array)/sizeof(array[0]))
+#endif
+
+static int
+__get_ether_addr(int ifindex, u_char *lladdr)
+{
+ int mib[6];
+ char *buf;
+ struct if_msghdr *ifm;
+ char *lim;
+ char *next;
+ struct sockaddr_dl *sdl;
+ size_t len;
+
+ mib[0] = CTL_NET;
+ mib[1] = PF_ROUTE;
+ mib[2] = 0;
+ mib[3] = 0;
+ mib[4] = NET_RT_IFLIST;
+ mib[5] = ifindex;
+
+ if (sysctl(mib, elementsof(mib), NULL, &len, NULL, 0) != 0) {
+ daemon_log(LOG_ERR, "sysctl(NET_RT_IFLIST): %s",
+ strerror(errno));
+ return (-1);
+ }
+
+ buf = malloc(len);
+ if (buf == NULL) {
+ daemon_log(LOG_ERR, "malloc(%d): %s", len, strerror(errno));
+ return (-1);
+ }
+
+ if (sysctl(mib, elementsof(mib), buf, &len, NULL, 0) != 0) {
+ daemon_log(LOG_ERR, "sysctl(NET_RT_IFLIST): %s",
+ strerror(errno));
+ free(buf);
+ return (-1);
+ }
+
+ lim = buf + len;
+ for (next = buf; next < lim; next += ifm->ifm_msglen) {
+ ifm = (struct if_msghdr *)next;
+ if (ifm->ifm_type == RTM_IFINFO) {
+ sdl = (struct sockaddr_dl *)(ifm + 1);
+ memcpy(lladdr, LLADDR(sdl), ETHER_ADDRLEN);
+ }
+ }
+ free(buf);
+
+ return (0);
+}
+
+static int
+open_socket(int iface, uint8_t *hw_address)
+{
+ struct bpf_program bpf;
+ char ifname[IFNAMSIZ];
+ pcap_t *pp;
+ int err;
+ int fd;
+
+ assert(__pp == NULL);
+
+ if (interface_up(iface) < 0) {
+ return (-1);
+ }
+ if (__get_ether_addr(iface, __lladdr) == -1) {
+ return (-1);
+ }
+ if (if_indextoname(iface, ifname) == NULL) {
+ return (-1);
+ }
+
+ pp = pcap_open_live(ifname, 1500, 0, 0, __pcap_errbuf);
+ if (pp == NULL) {
+ return (-1);
+ }
+ err = pcap_set_datalink(pp, DLT_EN10MB);
+ if (err == -1) {
+ daemon_log(LOG_ERR, "pcap_set_datalink: %s", pcap_geterr(pp));
+ pcap_close(pp);
+ return (-1);
+ }
+ err = pcap_setdirection(pp, PCAP_D_IN);
+ if (err == -1) {
+ daemon_log(LOG_ERR, "pcap_setdirection: %s", pcap_geterr(pp));
+ pcap_close(pp);
+ return (-1);
+ }
+
+ fd = pcap_get_selectable_fd(pp);
+ if (fd == -1) {
+ pcap_close(pp);
+ return (-1);
+ }
+#if 0
+ /* XXX: can we use this with pcap_next_ex() ? */
+ err = pcap_setnonblock(pp, 1, __pcap_errbuf);
+ if (err == -1) {
+ pcap_close(pp);
+ return (-1);
+ }
+#endif
+
+ err = pcap_compile(pp, &bpf,
+ "arp and ether dst ff:ff:ff:ff:ff:ff", 1, 0);
+ if (err == -1) {
+ daemon_log(LOG_ERR, "pcap_compile: %s", pcap_geterr(pp));
+ pcap_close(pp);
+ return (-1);
+ }
+ err = pcap_setfilter(pp, &bpf);
+ if (err == -1) {
+ daemon_log(LOG_ERR, "pcap_setfilter: %s", pcap_geterr(pp));
+ pcap_close(pp);
+ return (-1);
+ }
+ pcap_freecode(&bpf);
+
+ /* Stash pcap-specific context away. */
+ memcpy(hw_address, __lladdr, ETHER_ADDRLEN);
+ __pp = pp;
+
+ return (fd);
+}
+
+static void
+close_socket(int fd __unused)
+{
+
+ assert(__pp != NULL);
+ pcap_close(__pp);
+ __pp = NULL;
+}
+
+/*
+ * We trick avahi into allocating sizeof(packet) + sizeof(ether_header),
+ * and prepend the required ethernet header information before sending.
+ */
+static int
+send_packet(int fd __unused, int iface __unused, ArpPacket *packet,
+ size_t packet_len)
+{
+ struct ether_header *eh;
+
+ assert(__pp != NULL);
+ assert(packet != NULL);
+
+ eh = (struct ether_header *)packet->ether_header;
+ memset(eh->ether_dhost, 0xFF, ETHER_ADDRLEN);
+ memcpy(eh->ether_shost, __lladdr, ETHER_ADDRLEN);
+ eh->ether_type = htons(0x0806);
+
+ return (pcap_inject(__pp, (void *)eh, packet_len + sizeof(*eh)));
+}
+
+static int
+recv_packet(int fd __unused, ArpPacket **packet, size_t *packet_len)
+{
+ struct pcap_pkthdr *ph;
+ u_char *pd;
+ ArpPacket *ap;
+ int err;
+ int retval;
+
+ assert(__pp != NULL);
+ assert(packet != NULL);
+ assert(packet_len != NULL);
+
+ *packet = NULL;
+ *packet_len = 0;
+ retval = -1;
+
+ err = pcap_next_ex(__pp, &ph, (const u_char **)&pd);
+ if (err == 1 && ph->caplen <= ph->len) {
+ ap = packet_new(ph->caplen);
+ memcpy(ap->ether_header, pd, ph->caplen);
+ *packet = ap;
+ *packet_len = (ph->caplen - sizeof(struct ether_header));
+ retval = 0;
+ } else {
+ if (err == 1) {
+ daemon_log(LOG_ERR, "pcap len > caplen");
+ } else {
+ daemon_log(LOG_ERR, "pcap_next_ex: %s",
+ pcap_geterr(__pp));
+ }
+ }
+
+ return (retval);
+}
+#endif /* __linux__ */
+
int is_ll_address(uint32_t addr) {
return
(ntohl(addr) & IPV4LL_NETMASK) == IPV4LL_NETWORK &&
@@ -507,6 +767,7 @@ int is_ll_address(uint32_t addr) {
ntohl(addr) != IPV4LL_BROADCAST;
}
+
static struct timeval *elapse_time(struct timeval *tv, unsigned msec, unsigned jitter) {
assert(tv);
@@ -656,6 +917,9 @@ static int drop_privs(void) {
int r;
mode_t u;
+ pw = NULL;
+ gr = NULL;
+
/* Get user/group ID */
if (!no_drop_root) {
@@ -780,13 +1044,13 @@ static int loop(int iface, uint32_t addr) {
struct timeval next_wakeup;
int next_wakeup_valid = 0;
char buf[64];
- void *in_packet = NULL;
+ ArpPacket *in_packet = NULL;
size_t in_packet_len;
- void *out_packet = NULL;
+ ArpPacket *out_packet = NULL;
size_t out_packet_len;
uint8_t hw_address[ETHER_ADDRLEN];
struct pollfd pollfds[FD_MAX];
- int iface_fd;
+ int iface_fd = -1;
Event event = EVENT_NULL;
int retval_sent = !daemonize;
State st;
@@ -1054,7 +1318,7 @@ static int loop(int iface, uint32_t addr) {
if (pollfds[FD_ARP].revents == POLLERR) {
/* The interface is probably down, let's recreate our socket */
- close(fd);
+ close_socket(fd);
if ((fd = open_socket(iface, hw_address)) < 0)
goto fail;
@@ -1124,7 +1388,7 @@ fail:
avahi_free(in_packet);
if (fd >= 0)
- close(fd);
+ close_socket(fd);
if (iface_fd >= 0)
iface_done();
generated by cgit (git 2.34.1) at 2024-04-29 02:26:10 +0000