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Minor code simplification (don't store received pbuf, change conditional code to assert where applicable), check pbuf length before testing for valid reply

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goldsimon 2009-10-19 20:06:01 +00:00
parent a37e62b7d0
commit 67411c4299
3 changed files with 35 additions and 33 deletions
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5
CHANGELOG
View File

@ -43,6 +43,11 @@ HISTORY
++ Bugfixes: ++ Bugfixes:
2009-10-19: Simon Goldschmidt
* dhcp.c/.h: Minor code simplification (don't store received pbuf, change
conditional code to assert where applicable), check pbuf length before
testing for valid reply
2009-10-19: Simon Goldschmidt 2009-10-19: Simon Goldschmidt
* dhcp.c: Removed most calls to udp_connect since they aren't necessary * dhcp.c: Removed most calls to udp_connect since they aren't necessary
when using udp_sendto_if() - always stay connected to IP_ADDR_ANY. when using udp_sendto_if() - always stay connected to IP_ADDR_ANY.

59
src/core/dhcp.c
View File

@ -99,6 +99,8 @@
* MTU is checked to be big enough in dhcp_start */ * MTU is checked to be big enough in dhcp_start */
#define DHCP_MAX_MSG_LEN(netif) (netif->mtu) #define DHCP_MAX_MSG_LEN(netif) (netif->mtu)
#define DHCP_MAX_MSG_LEN_MIN_REQUIRED 576 #define DHCP_MAX_MSG_LEN_MIN_REQUIRED 576
/** Minimum length for reply before packet is parsed */
#define DHCP_MIN_REPLY_LEN 44
#define REBOOT_TRIES 2 #define REBOOT_TRIES 2
@ -120,7 +122,7 @@ static void dhcp_set_state(struct dhcp *dhcp, u8_t new_state);
/* receive, unfold, parse and free incoming messages */ /* receive, unfold, parse and free incoming messages */
static void dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port); static void dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port);
static err_t dhcp_unfold_reply(struct dhcp *dhcp); static err_t dhcp_unfold_reply(struct dhcp *dhcp, struct pbuf *p);
static u8_t *dhcp_get_option_ptr(struct dhcp *dhcp, u8_t option_type); static u8_t *dhcp_get_option_ptr(struct dhcp *dhcp, u8_t option_type);
static u8_t dhcp_get_option_byte(u8_t *ptr); static u8_t dhcp_get_option_byte(u8_t *ptr);
#if 0 #if 0
@ -613,9 +615,9 @@ dhcp_start(struct netif *netif)
if (dhcp->pcb != NULL) { if (dhcp->pcb != NULL) {
udp_remove(dhcp->pcb); udp_remove(dhcp->pcb);
} }
if (dhcp->p != NULL) { LWIP_ASSERT("pbuf p_out wasn't freed", dhcp->p_out == NULL);
pbuf_free(dhcp->p); LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL &&
} dhcp->options_in == NULL && dhcp->options_in_len == 0);
} }
/* clear data structure */ /* clear data structure */
@ -661,14 +663,13 @@ dhcp_start(struct netif *netif)
void void
dhcp_inform(struct netif *netif) dhcp_inform(struct netif *netif)
{ {
struct dhcp *dhcp, *old_dhcp = netif->dhcp; struct dhcp *dhcp, *old_dhcp;
err_t result = ERR_OK; err_t result = ERR_OK;
dhcp = mem_malloc(sizeof(struct dhcp)); dhcp = mem_malloc(sizeof(struct dhcp));
if (dhcp == NULL) { if (dhcp == NULL) {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_inform(): could not allocate dhcp\n")); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_inform(): could not allocate dhcp\n"));
return; return;
} }
netif->dhcp = dhcp;
memset(dhcp, 0, sizeof(struct dhcp)); memset(dhcp, 0, sizeof(struct dhcp));
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): allocated dhcp\n")); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): allocated dhcp\n"));
@ -676,9 +677,10 @@ dhcp_inform(struct netif *netif)
if (dhcp->pcb == NULL) { if (dhcp->pcb == NULL) {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_inform(): could not obtain pcb")); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_inform(): could not obtain pcb"));
mem_free((void *)dhcp); mem_free((void *)dhcp);
netif->dhcp = old_dhcp;
return; return;
} }
old_dhcp = netif->dhcp;
netif->dhcp = dhcp;
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): created new udp pcb\n")); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): created new udp pcb\n"));
/* create and initialize the DHCP message header */ /* create and initialize the DHCP message header */
result = dhcp_create_request(netif); result = dhcp_create_request(netif);
@ -705,9 +707,7 @@ dhcp_inform(struct netif *netif)
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_inform: could not allocate DHCP request\n")); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_inform: could not allocate DHCP request\n"));
} }
if (dhcp->pcb != NULL) { udp_remove(dhcp->pcb);
udp_remove(dhcp->pcb);
}
dhcp->pcb = NULL; dhcp->pcb = NULL;
mem_free((void *)dhcp); mem_free((void *)dhcp);
netif->dhcp = old_dhcp; netif->dhcp = old_dhcp;
@ -1213,12 +1213,8 @@ dhcp_stop(struct netif *netif)
udp_remove(dhcp->pcb); udp_remove(dhcp->pcb);
dhcp->pcb = NULL; dhcp->pcb = NULL;
} }
if (dhcp->p != NULL) { LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL &&
pbuf_free(dhcp->p); dhcp->options_in == NULL && dhcp->options_in_len == 0);
dhcp->p = NULL;
}
/* free unfolded reply */
dhcp_free_reply(dhcp);
mem_free((void *)dhcp); mem_free((void *)dhcp);
netif->dhcp = NULL; netif->dhcp = NULL;
} }
@ -1292,16 +1288,15 @@ dhcp_option_long(struct dhcp *dhcp, u32_t value)
* *
*/ */
static err_t static err_t
dhcp_unfold_reply(struct dhcp *dhcp) dhcp_unfold_reply(struct dhcp *dhcp, struct pbuf *p)
{ {
u16_t ret; u16_t ret;
LWIP_ERROR("dhcp != NULL", (dhcp != NULL), return ERR_ARG;); LWIP_ERROR("dhcp != NULL", (dhcp != NULL), return ERR_ARG;);
LWIP_ERROR("dhcp->p != NULL", (dhcp->p != NULL), return ERR_VAL;);
/* free any left-overs from previous unfolds */ /* free any left-overs from previous unfolds */
dhcp_free_reply(dhcp); dhcp_free_reply(dhcp);
/* options present? */ /* options present? */
if (dhcp->p->tot_len > (sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN)) { if (p->tot_len > (sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN)) {
dhcp->options_in_len = dhcp->p->tot_len - (sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN); dhcp->options_in_len = p->tot_len - (sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN);
dhcp->options_in = mem_malloc(dhcp->options_in_len); dhcp->options_in = mem_malloc(dhcp->options_in_len);
if (dhcp->options_in == NULL) { if (dhcp->options_in == NULL) {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_unfold_reply(): could not allocate dhcp->options\n")); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_unfold_reply(): could not allocate dhcp->options\n"));
@ -1313,7 +1308,7 @@ dhcp_unfold_reply(struct dhcp *dhcp)
if (dhcp->msg_in == NULL) { if (dhcp->msg_in == NULL) {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_unfold_reply(): could not allocate dhcp->msg_in\n")); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_unfold_reply(): could not allocate dhcp->msg_in\n"));
if (dhcp->options_in != NULL) { if (dhcp->options_in != NULL) {
mem_free((void *)dhcp->options_in); mem_free(dhcp->options_in);
dhcp->options_in = NULL; dhcp->options_in = NULL;
dhcp->options_in_len = 0; dhcp->options_in_len = 0;
} }
@ -1321,14 +1316,14 @@ dhcp_unfold_reply(struct dhcp *dhcp)
} }
/** copy the DHCP message without options */ /** copy the DHCP message without options */
ret = pbuf_copy_partial(dhcp->p, dhcp->msg_in, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN, 0); ret = pbuf_copy_partial(p, dhcp->msg_in, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN, 0);
LWIP_ASSERT("ret == sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN", ret == sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN); LWIP_ASSERT("ret == sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN", ret == sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_unfold_reply(): copied %"U16_F" bytes into dhcp->msg_in[]\n", LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_unfold_reply(): copied %"U16_F" bytes into dhcp->msg_in[]\n",
sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN)); sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN));
if (dhcp->options_in != NULL) { if (dhcp->options_in != NULL) {
/** copy the DHCP options */ /** copy the DHCP options */
ret = pbuf_copy_partial(dhcp->p, dhcp->options_in, dhcp->options_in_len, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN); ret = pbuf_copy_partial(p, dhcp->options_in, dhcp->options_in_len, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN);
LWIP_ASSERT("ret == dhcp->options_in_len", ret == dhcp->options_in_len); LWIP_ASSERT("ret == dhcp->options_in_len", ret == dhcp->options_in_len);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_unfold_reply(): copied %"U16_F" bytes to dhcp->options_in[]\n", LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_unfold_reply(): copied %"U16_F" bytes to dhcp->options_in[]\n",
dhcp->options_in_len)); dhcp->options_in_len));
@ -1340,7 +1335,6 @@ dhcp_unfold_reply(struct dhcp *dhcp)
/** /**
* Free the incoming DHCP message including contiguous copy of * Free the incoming DHCP message including contiguous copy of
* its DHCP options. * its DHCP options.
*
*/ */
static void dhcp_free_reply(struct dhcp *dhcp) static void dhcp_free_reply(struct dhcp *dhcp)
{ {
@ -1349,14 +1343,13 @@ static void dhcp_free_reply(struct dhcp *dhcp)
dhcp->msg_in = NULL; dhcp->msg_in = NULL;
} }
if (dhcp->options_in) { if (dhcp->options_in) {
mem_free((void *)dhcp->options_in); mem_free(dhcp->options_in);
dhcp->options_in = NULL; dhcp->options_in = NULL;
dhcp->options_in_len = 0; dhcp->options_in_len = 0;
} }
LWIP_DEBUGF(DHCP_DEBUG, ("dhcp_free_reply(): free'd\n")); LWIP_DEBUGF(DHCP_DEBUG, ("dhcp_free_reply(): free'd\n"));
} }
/** /**
* If an incoming DHCP message is in response to us, then trigger the state machine * If an incoming DHCP message is in response to us, then trigger the state machine
*/ */
@ -1377,8 +1370,15 @@ static void dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_
LWIP_UNUSED_ARG(pcb); LWIP_UNUSED_ARG(pcb);
LWIP_UNUSED_ARG(addr); LWIP_UNUSED_ARG(addr);
LWIP_UNUSED_ARG(port); LWIP_UNUSED_ARG(port);
dhcp->p = p;
/* TODO: check packet length before reading them */ LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL &&
dhcp->options_in == NULL && dhcp->options_in_len == 0);
if (p->len < DHCP_MIN_REPLY_LEN) {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 1, ("DHCP reply message too short\n"));
goto free_pbuf_and_return;
}
if (reply_msg->op != DHCP_BOOTREPLY) { if (reply_msg->op != DHCP_BOOTREPLY) {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 1, ("not a DHCP reply message, but type %"U16_F"\n", (u16_t)reply_msg->op)); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 1, ("not a DHCP reply message, but type %"U16_F"\n", (u16_t)reply_msg->op));
goto free_pbuf_and_return; goto free_pbuf_and_return;
@ -1397,7 +1397,7 @@ static void dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_
goto free_pbuf_and_return; goto free_pbuf_and_return;
} }
/* option fields could be unfold? */ /* option fields could be unfold? */
if (dhcp_unfold_reply(dhcp) != ERR_OK) { if (dhcp_unfold_reply(dhcp, p) != ERR_OK) {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("problem unfolding DHCP message - too short on memory?\n")); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("problem unfolding DHCP message - too short on memory?\n"));
goto free_pbuf_and_return; goto free_pbuf_and_return;
} }
@ -1451,7 +1451,6 @@ static void dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_
free_pbuf_and_return: free_pbuf_and_return:
dhcp_free_reply(dhcp); dhcp_free_reply(dhcp);
pbuf_free(p); pbuf_free(p);
dhcp->p = NULL;
} }
/** /**

4
src/include/lwip/dhcp.h
View File

@ -32,12 +32,10 @@ struct dhcp
u32_t xid; u32_t xid;
/** our connection to the DHCP server */ /** our connection to the DHCP server */
struct udp_pcb *pcb; struct udp_pcb *pcb;
/** (first) pbuf of incoming msg */
struct pbuf *p;
/** incoming msg */ /** incoming msg */
struct dhcp_msg *msg_in; struct dhcp_msg *msg_in;
/** incoming msg options */ /** incoming msg options */
struct dhcp_msg *options_in; void *options_in;
/** ingoing msg options length */ /** ingoing msg options length */
u16_t options_in_len; u16_t options_in_len;