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https://gitlab.isc.org/isc-projects/dhcp
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Merged #28761 (Linux interface discovery)
This commit is contained in:
Francis Dupont
parent
66e800337e
commit
e191f1e8de
10
RELNOTES
10
RELNOTES
@ -985,6 +985,16 @@ by Eric Young (eay@cryptsoft.com).
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"Run out of memory." on the standard error and exists with status 1.
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[ISC-Bugs #32744]
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- The linux interface discovery code has been modified to use getifaddrs()
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as is done for BSD and OS-X. Prior to this the code would only recognize
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the first address on an interface and thereby omit vlans.
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Thanks to Jiri Popelka at Redhat, Marius Tomaschewski at Suse, and Wei
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Kong at Novell, who all submitted patches.
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[ISC-Bugs #28761]
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[ISC-Bugs #31992]
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[ISC-Bugs #25428]
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[ISC-Bugs #31940]
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Changes since 4.2.0 (new features)
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- If a client renews before 'dhcp-cache-threshold' percent of its lease
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@ -373,392 +373,13 @@ end_iface_scan(struct iface_conf_list *ifaces) {
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ifaces->sock = -1;
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}
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#elif __linux /* !HAVE_SIOCGLIFCONF */
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/*
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* Linux support
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* -------------
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*
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* In Linux, we use the /proc pseudo-filesystem to get information
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* about interfaces, along with selected ioctl() calls.
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*
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* Linux low level access is documented in the netdevice man page.
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*/
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/*
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* Structure holding state about the scan.
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*/
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struct iface_conf_list {
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int sock; /* file descriptor used to get information */
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FILE *fp; /* input from /proc/net/dev */
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#ifdef DHCPv6
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FILE *fp6; /* input from /proc/net/if_inet6 */
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#endif
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};
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/*
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* Structure used to return information about a specific interface.
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*/
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struct iface_info {
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char name[IFNAMSIZ]; /* name of the interface, e.g. "eth0" */
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struct sockaddr_storage addr; /* address information */
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isc_uint64_t flags; /* interface flags, e.g. IFF_LOOPBACK */
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};
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/*
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* Start a scan of interfaces.
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*
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* The iface_conf_list structure maintains state for this process.
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*/
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int
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begin_iface_scan(struct iface_conf_list *ifaces) {
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char buf[IF_LINE_LENGTH];
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int len;
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int i;
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ifaces->fp = fopen("/proc/net/dev", "r");
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if (ifaces->fp == NULL) {
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log_error("Error opening '/proc/net/dev' to list interfaces");
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return 0;
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}
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/*
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* The first 2 lines are header information, so read and ignore them.
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*/
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for (i=0; i<2; i++) {
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if (fgets(buf, sizeof(buf), ifaces->fp) == NULL) {
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log_error("Error reading headers from '/proc/net/dev'");
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fclose(ifaces->fp);
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ifaces->fp = NULL;
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return 0;
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}
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len = strlen(buf);
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if ((len <= 0) || (buf[len-1] != '\n')) {
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log_error("Bad header line in '/proc/net/dev'");
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fclose(ifaces->fp);
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ifaces->fp = NULL;
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return 0;
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}
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}
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ifaces->sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
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if (ifaces->sock < 0) {
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log_error("Error creating socket to list interfaces; %m");
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fclose(ifaces->fp);
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ifaces->fp = NULL;
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return 0;
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}
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#ifdef DHCPv6
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if (local_family == AF_INET6) {
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ifaces->fp6 = fopen("/proc/net/if_inet6", "r");
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if (ifaces->fp6 == NULL) {
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log_error("Error opening '/proc/net/if_inet6' to "
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"list IPv6 interfaces; %m");
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close(ifaces->sock);
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ifaces->sock = -1;
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fclose(ifaces->fp);
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ifaces->fp = NULL;
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return 0;
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}
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}
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#endif
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return 1;
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}
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/*
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* Read our IPv4 interfaces from /proc/net/dev.
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*
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* The file looks something like this:
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*
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* Inter-| Receive ...
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* face |bytes packets errs drop fifo frame ...
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* lo: 1580562 4207 0 0 0 0 ...
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* eth0: 0 0 0 0 0 0 ...
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* eth1:1801552440 37895 0 14 0 ...
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*
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* We only care about the interface name, which is at the start of
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* each line.
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*
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* We use an ioctl() to get the address and flags for each interface.
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*/
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static int
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next_iface4(struct iface_info *info, int *err, struct iface_conf_list *ifaces) {
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char buf[IF_LINE_LENGTH];
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int len;
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char *p;
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char *name;
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struct ifreq tmp;
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/*
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* Loop exits when we find an interface that has an address, or
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* when we run out of interfaces.
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*/
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for (;;) {
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do {
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/*
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* Read the next line in the file.
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*/
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if (fgets(buf, sizeof(buf), ifaces->fp) == NULL) {
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if (ferror(ifaces->fp)) {
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*err = 1;
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log_error("Error reading interface "
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"information");
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} else {
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*err = 0;
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}
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return 0;
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}
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/*
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* Make sure the line is a nice,
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* newline-terminated line.
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*/
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len = strlen(buf);
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if ((len <= 0) || (buf[len-1] != '\n')) {
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log_error("Bad line reading interface "
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"information");
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*err = 1;
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return 0;
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}
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/*
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* Figure out our name.
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*/
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p = strrchr(buf, ':');
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if (p == NULL) {
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log_error("Bad line reading interface "
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"information (no colon)");
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*err = 1;
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return 0;
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}
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*p = '\0';
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name = buf;
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while (isspace(*name)) {
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name++;
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}
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/*
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* Copy our name into our interface structure.
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*/
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len = p - name;
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if (len >= sizeof(info->name)) {
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*err = 1;
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log_error("Interface name '%s' too long", name);
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return 0;
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}
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strncpy(info->name, name, sizeof(info->name) - 1);
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#ifdef ALIAS_NAMED_PERMUTED
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/* interface aliases look like "eth0:1" or "wlan1:3" */
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s = strchr(info->name, ':');
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if (s != NULL) {
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*s = '\0';
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}
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#endif
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#ifdef SKIP_DUMMY_INTERFACES
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} while (strncmp(info->name, "dummy", 5) == 0);
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#else
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} while (0);
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#endif
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memset(&tmp, 0, sizeof(tmp));
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strncpy(tmp.ifr_name, name, sizeof(tmp.ifr_name) - 1);
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if (ioctl(ifaces->sock, SIOCGIFADDR, &tmp) < 0) {
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if (errno == EADDRNOTAVAIL) {
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continue;
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}
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log_error("Error getting interface address "
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"for '%s'; %m", name);
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*err = 1;
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return 0;
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}
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memcpy(&info->addr, &tmp.ifr_addr, sizeof(tmp.ifr_addr));
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memset(&tmp, 0, sizeof(tmp));
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strncpy(tmp.ifr_name, name, sizeof(tmp.ifr_name) - 1);
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if (ioctl(ifaces->sock, SIOCGIFFLAGS, &tmp) < 0) {
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log_error("Error getting interface flags for '%s'; %m",
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name);
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*err = 1;
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return 0;
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}
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info->flags = tmp.ifr_flags;
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*err = 0;
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return 1;
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}
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}
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#ifdef DHCPv6
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/*
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* Read our IPv6 interfaces from /proc/net/if_inet6.
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*
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* The file looks something like this:
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*
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* fe80000000000000025056fffec00008 05 40 20 80 vmnet8
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* 00000000000000000000000000000001 01 80 10 80 lo
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* fe80000000000000025056fffec00001 06 40 20 80 vmnet1
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* 200108881936000202166ffffe497d9b 03 40 00 00 eth1
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* fe8000000000000002166ffffe497d9b 03 40 20 80 eth1
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*
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* We get IPv6 address from the start, the interface name from the end,
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* and ioctl() to get flags.
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*/
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static int
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next_iface6(struct iface_info *info, int *err, struct iface_conf_list *ifaces) {
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char buf[IF_LINE_LENGTH];
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int len;
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char *p;
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char *name;
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int i;
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struct sockaddr_in6 addr;
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struct ifreq tmp;
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do {
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/*
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* Read the next line in the file.
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*/
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if (fgets(buf, sizeof(buf), ifaces->fp6) == NULL) {
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if (ferror(ifaces->fp6)) {
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*err = 1;
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log_error("Error reading IPv6 "
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"interface information");
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} else {
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*err = 0;
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}
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return 0;
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}
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/*
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* Make sure the line is a nice, newline-terminated line.
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*/
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len = strlen(buf);
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if ((len <= 0) || (buf[len-1] != '\n')) {
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log_error("Bad line reading IPv6 "
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"interface information");
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*err = 1;
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return 0;
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}
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/*
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* Figure out our name.
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*/
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buf[--len] = '\0';
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p = strrchr(buf, ' ');
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if (p == NULL) {
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log_error("Bad line reading IPv6 interface "
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"information (no space)");
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*err = 1;
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return 0;
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}
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name = p+1;
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/*
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* Copy our name into our interface structure.
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*/
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len = strlen(name);
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if (len >= sizeof(info->name)) {
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*err = 1;
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log_error("IPv6 interface name '%s' too long", name);
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return 0;
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}
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strncpy(info->name, name, sizeof(info->name) - 1);
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#ifdef SKIP_DUMMY_INTERFACES
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} while (strncmp(info->name, "dummy", 5) == 0);
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#else
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} while (0);
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#endif
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/*
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* Double-check we start with the IPv6 address.
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*/
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for (i=0; i<32; i++) {
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if (!isxdigit(buf[i]) || isupper(buf[i])) {
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*err = 1;
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log_error("Bad line reading IPv6 interface address "
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"for '%s'", name);
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return 0;
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}
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}
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/*
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* Load our socket structure.
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*/
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memset(&addr, 0, sizeof(addr));
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addr.sin6_family = AF_INET6;
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for (i=0; i<16; i++) {
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unsigned char byte;
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static const char hex[] = "0123456789abcdef";
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byte = ((index(hex, buf[i * 2]) - hex) << 4) |
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(index(hex, buf[i * 2 + 1]) - hex);
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addr.sin6_addr.s6_addr[i] = byte;
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}
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memcpy(&info->addr, &addr, sizeof(addr));
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/*
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* Get our flags.
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*/
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memset(&tmp, 0, sizeof(tmp));
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strncpy(tmp.ifr_name, name, sizeof(tmp.ifr_name) - 1);
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if (ioctl(ifaces->sock, SIOCGIFFLAGS, &tmp) < 0) {
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log_error("Error getting interface flags for '%s'; %m", name);
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*err = 1;
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return 0;
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}
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info->flags = tmp.ifr_flags;
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*err = 0;
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return 1;
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}
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#endif /* DHCPv6 */
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/*
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* Retrieve the next interface.
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*
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* Returns information in the info structure.
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* Sets err to 1 if there is an error, otherwise 0.
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*/
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int
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next_iface(struct iface_info *info, int *err, struct iface_conf_list *ifaces) {
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memset(info, 0, sizeof(struct iface_info));
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if (next_iface4(info, err, ifaces)) {
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return 1;
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}
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#ifdef DHCPv6
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if (!(*err)) {
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if (local_family == AF_INET6)
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return next_iface6(info, err, ifaces);
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}
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#endif
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return 0;
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}
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/*
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* End scan of interfaces.
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*/
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void
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end_iface_scan(struct iface_conf_list *ifaces) {
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fclose(ifaces->fp);
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ifaces->fp = NULL;
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close(ifaces->sock);
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ifaces->sock = -1;
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#ifdef DHCPv6
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if (local_family == AF_INET6) {
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fclose(ifaces->fp6);
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ifaces->fp6 = NULL;
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}
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#endif
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}
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#else
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/*
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* BSD support
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* BSD/Linux support
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* -----------
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*
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* FreeBSD, NetBSD, OpenBSD, and OS X all have the getifaddrs()
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* FreeBSD, NetBSD, OpenBSD, OS X/macOS and Linux all have the getifaddrs()
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* function.
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*
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* The getifaddrs() man page describes the use.
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@ -806,6 +427,8 @@ begin_iface_scan(struct iface_conf_list *ifaces) {
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*/
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int
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next_iface(struct iface_info *info, int *err, struct iface_conf_list *ifaces) {
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size_t sa_len = 0;
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if (ifaces->next == NULL) {
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*err = 0;
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return 0;
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@ -818,8 +441,23 @@ next_iface(struct iface_info *info, int *err, struct iface_conf_list *ifaces) {
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}
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memset(info, 0, sizeof(struct iface_info));
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strncpy(info->name, ifaces->next->ifa_name, sizeof(info->name) - 1);
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memcpy(&info->addr, ifaces->next->ifa_addr,
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ifaces->next->ifa_addr->sa_len);
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memset(&info->addr, 0 , sizeof(info->addr));
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/*
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* getifaddrs() can on Linux with some interfaces like PPP or TEQL
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* result in a record with no address (ifa_addr).
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*/
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if (ifaces->next->ifa_addr != NULL) {
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/* Linux lacks the sa_len member in struct sockaddr. */
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#if defined(__linux)
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if (ifaces->next->ifa_addr->sa_family == AF_INET)
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sa_len = sizeof(struct sockaddr_in);
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else if (ifaces->next->ifa_addr->sa_family == AF_INET6)
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sa_len = sizeof(struct sockaddr_in6);
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#else
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sa_len = ifaces->next->ifa_addr->sa_len;
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#endif
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memcpy(&info->addr, ifaces->next->ifa_addr, sa_len);
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}
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info->flags = ifaces->next->ifa_flags;
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ifaces->next = ifaces->next->ifa_next;
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*err = 0;
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