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Rework DHCP PCB handling: Old code registered one UDP PCB per netif where DHCP was active and there was a special case in udp_input() for this. New implementation uses one PCB for all netifs and removes special case in udp_input().

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The old approach called udp_bind() on each of the PCBs, which puts them into udp_pcbs list. The PCBs were iterated on all non-DHCP udp_inputs() with no effect.
My cleanup removes the special handling in udp.c, and uses only one DHCP UDP PCB to catch all DHCP messages from all netifs. The dhcp_recv function then checks whether ip_current_input_netif() has DHCP enabled - if not, the message is ignored. The PCB is only created/registered when one or more PCBs have DHCP enabled.
This commit is contained in:
Dirk Ziegelmeier 2016-02-28 15:31:00 +01:00
parent 42c92f80f1
commit 6aed6e659f
3 changed files with 127 additions and 114 deletions
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130
src/core/ipv4/dhcp.c
View File

@ -158,6 +158,8 @@ static u8_t xid_initialised;
#define dhcp_get_option_value(dhcp, idx) (dhcp_rx_options_val[idx])
#define dhcp_set_option_value(dhcp, idx, val) (dhcp_rx_options_val[idx] = (val))
static struct udp_pcb *dhcp_pcb;
static u8_t dhcp_pcb_refcount;
/* DHCP client state machine functions */
static err_t dhcp_discover(struct netif *netif);
@ -195,6 +197,46 @@ static void dhcp_option_hostname(struct dhcp *dhcp, struct netif *netif);
/* always add the DHCP options trailer to end and pad */
static void dhcp_option_trailer(struct dhcp *dhcp);
/** Ensure DHCP PCB is allocated and bound */
static err_t
dhcp_inc_pcb_refcount(void)
{
if(dhcp_pcb_refcount == 0) {
LWIP_ASSERT("dhcp_inc_pcb_refcount(): memory leak", dhcp_pcb == NULL);
/* allocate UDP PCB */
dhcp_pcb = udp_new();
if(dhcp_pcb == NULL) {
return ERR_MEM;
}
ip_set_option(dhcp_pcb, SOF_BROADCAST);
/* set up local and remote port for the pcb -> listen on all interfaces on all src/dest IPs */
udp_bind(dhcp_pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
udp_connect(dhcp_pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
udp_recv(dhcp_pcb, dhcp_recv, NULL);
}
dhcp_pcb_refcount++;
return ERR_OK;
}
/** Free DHCP PCB if the last netif stops using it */
static void
dhcp_dec_pcb_refcount(void)
{
LWIP_ASSERT("dhcp_pcb_refcount(): refcount error", (dhcp_pcb_refcount > 0));
dhcp_pcb_refcount--;
if(dhcp_pcb_refcount == 0) {
udp_remove(dhcp_pcb);
dhcp_pcb = NULL;
}
}
/**
* Back-off the DHCP client (because of a received NAK response).
*
@ -329,7 +371,7 @@ dhcp_select(struct netif *netif)
pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
/* send broadcast to any DHCP server */
udp_sendto_if_src(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif, IP_ADDR_ANY);
udp_sendto_if_src(dhcp_pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif, IP_ADDR_ANY);
dhcp_delete_msg(dhcp);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_select: REQUESTING\n"));
} else {
@ -679,35 +721,32 @@ dhcp_start(struct netif *netif)
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): could not allocate dhcp\n"));
return ERR_MEM;
}
/* store this dhcp client in the netif */
netif->dhcp = dhcp;
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): allocated dhcp"));
/* already has DHCP client attached */
} else {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_start(): restarting DHCP configuration\n"));
if (dhcp->pcb != NULL) {
udp_remove(dhcp->pcb);
}
LWIP_ASSERT("pbuf p_out wasn't freed", dhcp->p_out == NULL);
LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL );
if(dhcp->pcb_allocated != 0) {
dhcp_dec_pcb_refcount(); /* free DHCP PCB if not needed any more */
}
/* dhcp is cleared below, no need to reset flag*/
}
/* clear data structure */
memset(dhcp, 0, sizeof(struct dhcp));
/* dhcp_set_state(&dhcp, DHCP_STATE_OFF); */
/* allocate UDP PCB */
dhcp->pcb = udp_new();
if (dhcp->pcb == NULL) {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): could not obtain pcb\n"));
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting DHCP configuration\n"));
if(dhcp_inc_pcb_refcount() != ERR_OK) { /* ensure DHCP PCB is allocated */
return ERR_MEM;
}
ip_set_option(dhcp->pcb, SOF_BROADCAST);
/* set up local and remote port for the pcb */
udp_bind(dhcp->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
/* set up the recv callback and argument */
udp_recv(dhcp->pcb, dhcp_recv, netif);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting DHCP configuration\n"));
dhcp->pcb_allocated = 1;
#if LWIP_DHCP_CHECK_LINK_UP
if (!netif_is_link_up(netif)) {
@ -717,6 +756,7 @@ dhcp_start(struct netif *netif)
}
#endif /* LWIP_DHCP_CHECK_LINK_UP */
/* (re)start the DHCP negotiation */
result = dhcp_discover(netif);
if (result != ERR_OK) {
@ -741,27 +781,16 @@ dhcp_inform(struct netif *netif)
{
struct dhcp dhcp;
err_t result = ERR_OK;
struct udp_pcb *pcb;
LWIP_ERROR("netif != NULL", (netif != NULL), return;);
if(dhcp_inc_pcb_refcount() != ERR_OK) { /* ensure DHCP PCB is allocated */
return;
}
memset(&dhcp, 0, sizeof(struct dhcp));
dhcp_set_state(&dhcp, DHCP_STATE_INFORMING);
if ((netif->dhcp != NULL) && (netif->dhcp->pcb != NULL)) {
/* re-use existing pcb */
pcb = netif->dhcp->pcb;
} else {
pcb = udp_new();
if (pcb == NULL) {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform(): could not obtain pcb"));
return;
}
dhcp.pcb = pcb;
ip_set_option(dhcp.pcb, SOF_BROADCAST);
udp_bind(dhcp.pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): created new udp pcb\n"));
}
/* create and initialize the DHCP message header */
result = dhcp_create_msg(netif, &dhcp, DHCP_INFORM);
if (result == ERR_OK) {
@ -773,16 +802,15 @@ dhcp_inform(struct netif *netif)
pbuf_realloc(dhcp.p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp.options_out_len);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_inform: INFORMING\n"));
udp_sendto_if(pcb, dhcp.p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
udp_sendto_if(dhcp_pcb, dhcp.p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
dhcp_delete_msg(&dhcp);
} else {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform: could not allocate DHCP request\n"));
}
if (dhcp.pcb != NULL) {
/* otherwise, the existing pcb was used */
udp_remove(dhcp.pcb);
}
dhcp_dec_pcb_refcount(); /* delete DHCP PCB if not needed any more */
}
/** Handle a possible change in the network configuration.
@ -878,7 +906,7 @@ dhcp_decline(struct netif *netif)
pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
/* per section 4.4.4, broadcast DECLINE messages */
udp_sendto_if_src(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif, IP_ADDR_ANY);
udp_sendto_if_src(dhcp_pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif, IP_ADDR_ANY);
dhcp_delete_msg(dhcp);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_decline: BACKING OFF\n"));
} else {
@ -929,7 +957,7 @@ dhcp_discover(struct netif *netif)
pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT)\n"));
udp_sendto_if_src(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif, IP_ADDR_ANY);
udp_sendto_if_src(dhcp_pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif, IP_ADDR_ANY);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: deleting()ing\n"));
dhcp_delete_msg(dhcp);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover: SELECTING\n"));
@ -1089,7 +1117,7 @@ dhcp_renew(struct netif *netif)
pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
udp_sendto_if(dhcp->pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif);
udp_sendto_if(dhcp_pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif);
dhcp_delete_msg(dhcp);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_renew: RENEWING\n"));
@ -1135,7 +1163,7 @@ dhcp_rebind(struct netif *netif)
pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
/* broadcast to server */
udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
udp_sendto_if(dhcp_pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
dhcp_delete_msg(dhcp);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind: REBINDING\n"));
} else {
@ -1178,7 +1206,7 @@ dhcp_reboot(struct netif *netif)
pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
/* broadcast to server */
udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
udp_sendto_if(dhcp_pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
dhcp_delete_msg(dhcp);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot: REBOOTING\n"));
} else {
@ -1243,7 +1271,7 @@ dhcp_release(struct netif *netif)
pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
udp_sendto_if(dhcp->pcb, dhcp->p_out, &server_ip_addr, DHCP_SERVER_PORT, netif);
udp_sendto_if(dhcp_pcb, dhcp->p_out, &server_ip_addr, DHCP_SERVER_PORT, netif);
dhcp_delete_msg(dhcp);
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_release: RELEASED, DHCP_STATE_OFF\n"));
} else {
@ -1278,12 +1306,13 @@ dhcp_stop(struct netif *netif)
}
#endif /* LWIP_DHCP_AUTOIP_COOP */
if (dhcp->pcb != NULL) {
udp_remove(dhcp->pcb);
dhcp->pcb = NULL;
}
LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL);
dhcp_set_state(dhcp, DHCP_STATE_OFF);
if(dhcp->pcb_allocated != 0) {
dhcp_dec_pcb_refcount(); /* free DHCP PCB if not needed any more */
dhcp->pcb_allocated = 0;
}
}
}
@ -1589,15 +1618,20 @@ decode_next:
static void
dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
{
struct netif *netif = (struct netif *)arg;
struct netif *netif = ip_current_input_netif();
struct dhcp *dhcp = netif->dhcp;
struct dhcp_msg *reply_msg = (struct dhcp_msg *)p->payload;
u8_t msg_type;
u8_t i;
#if LWIP_IPV6
LWIP_UNUSED_ARG(arg);
/* Caught DHCP message from netif that does not have DHCP enabled? -> not interested */
if((dhcp == NULL) || (dhcp->pcb_allocated == 0)) {
goto free_pbuf_and_return;
}
LWIP_ASSERT("invalid server address type", !IP_IS_V6(addr));
#endif /* LWIP_IPV6 */
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_recv(pbuf = %p) from DHCP server %"U16_F".%"U16_F".%"U16_F".%"U16_F" port %"U16_F"\n", (void*)p,
ip4_addr1_16(ip_2_ip4(addr)), ip4_addr2_16(ip_2_ip4(addr)), ip4_addr3_16(ip_2_ip4(addr)), ip4_addr4_16(ip_2_ip4(addr)), port));

21
src/core/udp.c
View File

@ -260,27 +260,7 @@ udp_input(struct pbuf *p, struct netif *inp)
ip_addr_debug_print(UDP_DEBUG, ip_current_src_addr());
LWIP_DEBUGF(UDP_DEBUG, (", %"U16_F")\n", ntohs(udphdr->src)));
#if LWIP_DHCP
pcb = NULL;
/* when LWIP_DHCP is active, packets to DHCP_CLIENT_PORT may only be processed by
the dhcp module, no other UDP pcb may use the local UDP port DHCP_CLIENT_PORT */
if (dest == DHCP_CLIENT_PORT) {
/* all packets for DHCP_CLIENT_PORT not coming from DHCP_SERVER_PORT are dropped! */
if (src == DHCP_SERVER_PORT) {
if ((inp->dhcp != NULL) && (inp->dhcp->pcb != NULL)) {
/* accept the packet if
(- broadcast or directed to us) -> DHCP is link-layer-addressed, local ip is always ANY!
- inp->dhcp->pcb->remote == ANY or iphdr->src
(no need to check for IPv6 since the dhcp struct always uses IPv4) */
if (ip_addr_isany_val(inp->dhcp->pcb->remote_ip) ||
ip_addr_cmp(&inp->dhcp->pcb->remote_ip, ip_current_src_addr())) {
pcb = inp->dhcp->pcb;
}
}
}
} else
#endif /* LWIP_DHCP */
{
prev = NULL;
uncon_pcb = NULL;
/* Iterate through the UDP pcb list for a matching pcb.
@ -328,7 +308,6 @@ udp_input(struct pbuf *p, struct netif *inp)
if (pcb == NULL) {
pcb = uncon_pcb;
}
}
/* Check checksum if this is a match or if it was directed at us. */
if (pcb != NULL) {

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

@ -59,10 +59,10 @@ struct dhcp
{
/** transaction identifier of last sent request */
u32_t xid;
/** our connection to the DHCP server */
struct udp_pcb *pcb;
/** incoming msg */
struct dhcp_msg *msg_in;
/** track PCB allocation state */
u8_t pcb_allocated;
/** current DHCP state machine state */
u8_t state;
/** retries of current request */