blob: 3c5349da540b5f929e6697c3d9012c6a99a7cadf [file] [log] [blame]
/* dnsmasq is Copyright (c) 2000-2012 Simon Kelley
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 dated June, 1991, or
(at your option) version 3 dated 29 June, 2007.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "dnsmasq.h"
#ifdef HAVE_DHCP
void dhcp_common_init(void)
{
/* These each hold a DHCP option max size 255
and get a terminating zero added */
daemon->dhcp_buff = safe_malloc(256);
daemon->dhcp_buff2 = safe_malloc(256);
daemon->dhcp_buff3 = safe_malloc(256);
/* dhcp_packet is used by v4 and v6, outpacket only by v6
sizeof(struct dhcp_packet) is as good an initial size as any,
even for v6 */
expand_buf(&daemon->dhcp_packet, sizeof(struct dhcp_packet));
#ifdef HAVE_DHCP6
if (daemon->dhcp6)
expand_buf(&daemon->outpacket, sizeof(struct dhcp_packet));
#endif
}
ssize_t recv_dhcp_packet(int fd, struct msghdr *msg)
{
ssize_t sz;
while (1)
{
msg->msg_flags = 0;
while ((sz = recvmsg(fd, msg, MSG_PEEK | MSG_TRUNC)) == -1 && errno == EINTR);
if (sz == -1)
return -1;
if (!(msg->msg_flags & MSG_TRUNC))
break;
/* Very new Linux kernels return the actual size needed,
older ones always return truncated size */
if ((size_t)sz == daemon->dhcp_packet.iov_len)
{
if (!expand_buf(&daemon->dhcp_packet, sz + 100))
return -1;
}
else
{
expand_buf(&daemon->dhcp_packet, sz);
break;
}
}
while ((sz = recvmsg(fd, msg, 0)) == -1 && errno == EINTR);
return (msg->msg_flags & MSG_TRUNC) ? -1 : sz;
}
struct dhcp_netid *run_tag_if(struct dhcp_netid *tags)
{
struct tag_if *exprs;
struct dhcp_netid_list *list;
for (exprs = daemon->tag_if; exprs; exprs = exprs->next)
if (match_netid(exprs->tag, tags, 1))
for (list = exprs->set; list; list = list->next)
{
list->list->next = tags;
tags = list->list;
}
return tags;
}
struct dhcp_netid *option_filter(struct dhcp_netid *tags, struct dhcp_netid *context_tags, struct dhcp_opt *opts)
{
struct dhcp_netid *tagif = run_tag_if(tags);
struct dhcp_opt *opt;
/* flag options which are valid with the current tag set (sans context tags) */
for (opt = opts; opt; opt = opt->next)
{
opt->flags &= ~DHOPT_TAGOK;
if (!(opt->flags & (DHOPT_ENCAPSULATE | DHOPT_VENDOR | DHOPT_RFC3925)) &&
match_netid(opt->netid, tagif, 0))
opt->flags |= DHOPT_TAGOK;
}
/* now flag options which are valid, including the context tags,
otherwise valid options are inhibited if we found a higher priotity one above */
if (context_tags)
{
struct dhcp_netid *last_tag;
for (last_tag = context_tags; last_tag->next; last_tag = last_tag->next);
last_tag->next = tags;
tagif = run_tag_if(context_tags);
for (opt = opts; opt; opt = opt->next)
if (!(opt->flags & (DHOPT_ENCAPSULATE | DHOPT_VENDOR | DHOPT_RFC3925 | DHOPT_TAGOK)) &&
match_netid(opt->netid, tagif, 0))
{
struct dhcp_opt *tmp;
for (tmp = opts; tmp; tmp = tmp->next)
if (tmp->opt == opt->opt && opt->netid && (tmp->flags & DHOPT_TAGOK))
break;
if (!tmp)
opt->flags |= DHOPT_TAGOK;
}
}
/* now flag untagged options which are not overridden by tagged ones */
for (opt = opts; opt; opt = opt->next)
if (!(opt->flags & (DHOPT_ENCAPSULATE | DHOPT_VENDOR | DHOPT_RFC3925 | DHOPT_TAGOK)) && !opt->netid)
{
struct dhcp_opt *tmp;
for (tmp = opts; tmp; tmp = tmp->next)
if (tmp->opt == opt->opt && (tmp->flags & DHOPT_TAGOK))
break;
if (!tmp)
opt->flags |= DHOPT_TAGOK;
else if (!tmp->netid)
my_syslog(MS_DHCP | LOG_WARNING, _("Ignoring duplicate dhcp-option %d"), tmp->opt);
}
return tagif;
}
/* Is every member of check matched by a member of pool?
If tagnotneeded, untagged is OK */
int match_netid(struct dhcp_netid *check, struct dhcp_netid *pool, int tagnotneeded)
{
struct dhcp_netid *tmp1;
if (!check && !tagnotneeded)
return 0;
for (; check; check = check->next)
{
/* '#' for not is for backwards compat. */
if (check->net[0] != '!' && check->net[0] != '#')
{
for (tmp1 = pool; tmp1; tmp1 = tmp1->next)
if (strcmp(check->net, tmp1->net) == 0)
break;
if (!tmp1)
return 0;
}
else
for (tmp1 = pool; tmp1; tmp1 = tmp1->next)
if (strcmp((check->net)+1, tmp1->net) == 0)
return 0;
}
return 1;
}
/* return domain or NULL if none. */
char *strip_hostname(char *hostname)
{
char *dot = strchr(hostname, '.');
if (!dot)
return NULL;
*dot = 0; /* truncate */
if (strlen(dot+1) != 0)
return dot+1;
return NULL;
}
void log_tags(struct dhcp_netid *netid, u32 xid)
{
if (netid && option_bool(OPT_LOG_OPTS))
{
char *s = daemon->namebuff;
for (*s = 0; netid; netid = netid->next)
{
/* kill dupes. */
struct dhcp_netid *n;
for (n = netid->next; n; n = n->next)
if (strcmp(netid->net, n->net) == 0)
break;
if (!n)
{
strncat (s, netid->net, (MAXDNAME-1) - strlen(s));
if (netid->next)
strncat (s, ", ", (MAXDNAME-1) - strlen(s));
}
}
my_syslog(MS_DHCP | LOG_INFO, _("%u tags: %s"), xid, s);
}
}
#endif