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More work on getting DHCP renewals to work properly
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@PherricOxide
PherricOxide committed Sep 25, 2013
1 parent 43456ff commit b03d369
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Showing 2 changed files with 82 additions and 11 deletions.
85 changes: 75 additions & 10 deletions dhcpclient.c
View file
Expand Up @@ -91,7 +91,7 @@ extern rand_t *honeyd_rand;

int need_dhcp = 0; /* set to one if a configuration specifies dhcp */

static struct timeval _timeout_tv = {1, 0};
static struct timeval _timeout_tv = {2, 0};

#define NTRIES 10

Expand All @@ -103,6 +103,7 @@ static int _bcast(struct template *,
static int _unicast(struct template *,
int (*)(struct dhcpclient_req *, void *, size_t *));
static void _dhcp_timeout_cb(int, short, void *);
static void _dhcp_renew_timeout_cb(int, short, void *);
static void _dhcp_reply(struct template *, u_char *, size_t);
static struct template * _dhcp_dequeue();
int _dhcp_getconf(struct template *);
Expand Down Expand Up @@ -229,8 +230,8 @@ _dhcp_getconf(struct template *tmpl)

req->ntries = 0;

req->timeoutev = evtimer_new(libevent_base, _dhcp_timeout_cb, tmpl);
evtimer_add(req->timeoutev, &_timeout_tv);
req->timeoutEv = evtimer_new(libevent_base, _dhcp_timeout_cb, tmpl);
evtimer_add(req->timeoutEv, &_timeout_tv);

return (0);
}
Expand Down Expand Up @@ -263,11 +264,33 @@ dhcp_abort(struct template *tmpl)
if (req->state == 0)
return;

event_del(req->timeoutev);
event_del(req->timeoutEv);

req->state = 0;
}

static void
_dhcp_renew_cb(int fd, short ev, void *arg)
{
struct template *tmpl = arg;
tmpl->dhcp_req->state = DHREQ_STATE_RENEWAL;
event_del(tmpl->dhcp_req->renewEv);

// Start a timer to trigger if the renew fails
tmpl->dhcp_req->renewTimeoutEv = evtimer_new(libevent_base, _dhcp_renew_timeout_cb, tmpl);
evtimer_add(tmpl->dhcp_req->renewTimeoutEv, &_timeout_tv);

_unicast(tmpl, _pack_renew);
}

static void
_dhcp_renew_timeout_cb(int fd, short ev, void *arg)
{
struct template *tmpl = arg;
event_del(tmpl->dhcp_req->renewTimeoutEv);
dhcp_template_new(tmpl);
}

static void
_dhcp_timeout_cb(int fd, short ev, void *arg)
{
Expand Down Expand Up @@ -300,7 +323,7 @@ _dhcp_timeout_cb(int fd, short ev, void *arg)
timeout_tv.tv_sec = 128;

timeout_tv.tv_usec = 0;
evtimer_add(req->timeoutev, &timeout_tv);
evtimer_add(req->timeoutEv, &timeout_tv);
}

static void
Expand Down Expand Up @@ -389,7 +412,7 @@ _dhcp_reply(struct template *tmpl, u_char *buf, size_t buflen)
if ((req->state & DHREQ_STATE_WAITANS) &&
(*opt1p == DH_MSGTYPE_OFFER))
replyreq = 1;
if ((req->state & DHREQ_STATE_WAITACK) &&
if ((req->state & DHREQ_STATE_WAITACK || req->state & DHREQ_STATE_RENEWAL) &&
(*opt1p == DH_MSGTYPE_ACK))
ack = 1;
break;
Expand All @@ -403,7 +426,6 @@ _dhcp_reply(struct template *tmpl, u_char *buf, size_t buflen)
case DH_LEASETIME:{
memcpy(&leaseTime, opt1p, sizeof(leaseTime));
leaseTime = ntohl(leaseTime);
printf("Lease time was %d seconds\n", leaseTime);
break;
}
case DH_SERVIDENT:
Expand Down Expand Up @@ -454,13 +476,34 @@ _dhcp_reply(struct template *tmpl, u_char *buf, size_t buflen)
struct addr addr = req->nc.hostaddr;
struct interface *inter = tmpl->inter;

// Set up renewal
if (leaseTime != 0)
{
req->renewTimer.tv_usec = 0;
req->renewTimer.tv_sec = leaseTime / 2;
req->renewEv = evtimer_new(libevent_base, _dhcp_renew_cb, tmpl);
evtimer_add(req->renewEv, &req->renewTimer);
}

// If this is a successful renewal, drop out here
if (req->state == DHREQ_STATE_RENEWAL)
{
syslog(LOG_NOTICE, "DHCP lease renewed with new lease of %d seconds\n", leaseTime);
req->state = DHREQ_STATE_GOTACK;

event_del(req->renewTimeoutEv);
return;
}

syslog(LOG_NOTICE, "[%s] got DHCP offer: %s",
inter->if_ent.intf_name, addr_ntoa(&addr));

dhcp_abort(tmpl);
//Abort resets the state variable, so we have to set it again afterward
req->state = DHREQ_STATE_GOTACK;



if (template_find(addr_ntoa(&addr)) != NULL) {
syslog(LOG_WARNING,
"%s: Already got a template named %s",
Expand Down Expand Up @@ -541,7 +584,7 @@ dhcp_recv_cb(struct eth_hdr *eth, struct ip_hdr *ip, u_short iplen)
return;
}

if (!(req->state & (DHREQ_STATE_WAITANS | DHREQ_STATE_WAITACK)))
if (!(req->state & (DHREQ_STATE_WAITANS | DHREQ_STATE_WAITACK | DHREQ_STATE_RENEWAL)))
return;

if (msglen != (iplen - (ip->ip_hl << 2) - UDP_HDR_LEN))
Expand Down Expand Up @@ -810,7 +853,6 @@ _pack_release(struct dhcpclient_req *req, void *buf, size_t *restlen)
return (0);
}

// TODO test and call this
static int
_pack_renew(struct dhcpclient_req *req, void *buf, size_t *restlen)
{
Expand Down Expand Up @@ -851,9 +893,32 @@ _pack_renew(struct dhcpclient_req *req, void *buf, size_t *restlen)
*restlen -= sizeof(*msg) + optlen;

if (*restlen >= padlen)
*restlen -= padlen; /* Fix for retarted DHCP servers. */
*restlen -= padlen;

return (0);
}


void
dhcp_template_new(struct template *tmpl)
{
struct addr addr;

/* Need to find a temporary IP address */
if (template_get_dhcp_address(&addr) == -1) {
syslog(LOG_ERR, "Failed to obtain temporary IP address.");
return;
}

template_remove_arp(tmpl);
template_remove(tmpl);
free(tmpl->name);

tmpl->name = strdup(addr_ntoa(&addr));
template_post_arp(tmpl, &addr);

queue_dhcp_discover(tmpl);
dhcp_send_discover();
}


8 changes: 7 additions & 1 deletion dhcpclient.h
View file
Expand Up @@ -76,14 +76,18 @@ struct netconf {
#define DHREQ_STATE_WAITANS 0x02
#define DHREQ_STATE_WAITACK 0x04
#define DHREQ_STATE_GOTACK 0x08
#define DHREQ_STATE_RENEWAL 0x10

struct dhcpclient_req {
int state;
eth_addr_t ea; /* our own */
eth_addr_t server_ea; /* from the server */
uint32_t xid;
struct event *timeoutev;
struct event *timeoutEv;
struct event *renewEv;
struct event *renewTimeoutEv;
struct timeval timer;
struct timeval renewTimer;
struct netconf nc;
struct addr servident;
int ntries;
Expand Down Expand Up @@ -142,4 +146,6 @@ void dhcp_send_discover();

void dhcp_recv_cb(struct eth_hdr *, struct ip_hdr *, u_short);

void dhcp_template_new(struct template *tmpl);

#endif /* _DHCPCLIENT_H */

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