Squashed 'lib/lwip/lwip/' content from commit 0a0452b2c39b

git-subtree-dir: lib/lwip/lwip
git-subtree-split: 0a0452b2c39bdd91e252aef045c115f88f6ca773

1 files changed, 533 insertions, 0 deletions

diff --git a/src/apps/netbiosns/netbiosns.c b/src/apps/netbiosns/netbiosns.c
new file mode 100644
index 00000000000..479c375b68b
--- /dev/null
+++ b/src/apps/netbiosns/netbiosns.c
@@ -0,0 +1,533 @@
+  /**
+ * @file
+ * NetBIOS name service responder
+ */
+
+/**
+ * @defgroup netbiosns NETBIOS responder
+ * @ingroup apps
+ *
+ * This is an example implementation of a NetBIOS name server.
+ * It responds to name queries for a configurable name.
+ * Name resolving is not supported.
+ *
+ * Note that the device doesn't broadcast it's own name so can't
+ * detect duplicate names!
+ */
+
+/*
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Modifications by Ray Abram to respond to NetBIOS name requests when Incoming name = *
+ * - based on code from "https://github.com/esp8266/Arduino/commit/1f7989b31d26d7df9776a08f36d685eae7ac8f99"
+ * - with permission to relicense to BSD from original author:
+ *   http://www.xpablo.cz/?p=751#more-751
+ */
+
+#include "lwip/apps/netbiosns.h"
+
+#if LWIP_IPV4 && LWIP_UDP  /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/def.h"
+#include "lwip/udp.h"
+#include "lwip/ip.h"
+#include "lwip/netif.h"
+#include "lwip/prot/iana.h"
+
+#include <string.h>
+
+/** size of a NetBIOS name */
+#define NETBIOS_NAME_LEN 16
+
+/** The Time-To-Live for NetBIOS name responds (in seconds)
+ * Default is 300000 seconds (3 days, 11 hours, 20 minutes) */
+#define NETBIOS_NAME_TTL 300000u
+
+/** NetBIOS header flags */
+#define NETB_HFLAG_RESPONSE           0x8000U
+#define NETB_HFLAG_OPCODE             0x7800U
+#define NETB_HFLAG_OPCODE_NAME_QUERY  0x0000U
+#define NETB_HFLAG_AUTHORATIVE        0x0400U
+#define NETB_HFLAG_TRUNCATED          0x0200U
+#define NETB_HFLAG_RECURS_DESIRED     0x0100U
+#define NETB_HFLAG_RECURS_AVAILABLE   0x0080U
+#define NETB_HFLAG_BROADCAST          0x0010U
+#define NETB_HFLAG_REPLYCODE          0x0008U
+#define NETB_HFLAG_REPLYCODE_NOERROR  0x0000U
+
+/* NetBIOS question types */
+#define NETB_QTYPE_NB                 0x0020U
+#define NETB_QTYPE_NBSTAT             0x0021U
+
+/** NetBIOS name flags */
+#define NETB_NFLAG_UNIQUE             0x8000U
+#define NETB_NFLAG_NODETYPE           0x6000U
+#define NETB_NFLAG_NODETYPE_HNODE     0x6000U
+#define NETB_NFLAG_NODETYPE_MNODE     0x4000U
+#define NETB_NFLAG_NODETYPE_PNODE     0x2000U
+#define NETB_NFLAG_NODETYPE_BNODE     0x0000U
+
+#define NETB_NFLAG_NAME_IN_CONFLICT   0x0800U /* 1=Yes, 0=No */
+#define NETB_NFLAG_NAME_IS_ACTIVE     0x0400U /* 1=Yes, 0=No */
+#define NETB_NFLAG_NAME_IS_PERMANENT  0x0200U /* 1=Yes (Name is Permanent Node Name), 0=No */
+
+/** NetBIOS message header */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct netbios_hdr {
+  PACK_STRUCT_FIELD(u16_t trans_id);
+  PACK_STRUCT_FIELD(u16_t flags);
+  PACK_STRUCT_FIELD(u16_t questions);
+  PACK_STRUCT_FIELD(u16_t answerRRs);
+  PACK_STRUCT_FIELD(u16_t authorityRRs);
+  PACK_STRUCT_FIELD(u16_t additionalRRs);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+/** NetBIOS message question part */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct netbios_question_hdr {
+  PACK_STRUCT_FLD_8(u8_t  nametype);
+  PACK_STRUCT_FLD_8(u8_t  encname[(NETBIOS_NAME_LEN * 2) + 1]);
+  PACK_STRUCT_FIELD(u16_t type);
+  PACK_STRUCT_FIELD(u16_t cls);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+/** NetBIOS message name part */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct netbios_name_hdr {
+  PACK_STRUCT_FLD_8(u8_t  nametype);
+  PACK_STRUCT_FLD_8(u8_t  encname[(NETBIOS_NAME_LEN * 2) + 1]);
+  PACK_STRUCT_FIELD(u16_t type);
+  PACK_STRUCT_FIELD(u16_t cls);
+  PACK_STRUCT_FIELD(u32_t ttl);
+  PACK_STRUCT_FIELD(u16_t datalen);
+  PACK_STRUCT_FIELD(u16_t flags);
+  PACK_STRUCT_FLD_S(ip4_addr_p_t addr);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+/** NetBIOS message */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct netbios_resp {
+  struct netbios_hdr      resp_hdr;
+  struct netbios_name_hdr resp_name;
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+/** The NBNS Structure Responds to a Name Query */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct netbios_answer {
+  struct netbios_hdr      answer_hdr;
+  /** the length of the next string */
+  PACK_STRUCT_FIELD(u8_t  name_size);
+  /** WARNING!!! this item may be of a different length (we use this struct for transmission) */
+  PACK_STRUCT_FLD_8(u8_t  query_name[(NETBIOS_NAME_LEN * 2) + 1]);
+  PACK_STRUCT_FIELD(u16_t packet_type);
+  PACK_STRUCT_FIELD(u16_t cls);
+  PACK_STRUCT_FIELD(u32_t ttl);
+  PACK_STRUCT_FIELD(u16_t data_length);
+#define OFFSETOF_STRUCT_NETBIOS_ANSWER_NUMBER_OF_NAMES 56
+  /** number of names */
+  PACK_STRUCT_FLD_8(u8_t  number_of_names);
+  /** node name */
+  PACK_STRUCT_FLD_8(u8_t  answer_name[NETBIOS_NAME_LEN]);
+  /** node flags */
+  PACK_STRUCT_FIELD(u16_t answer_name_flags);
+  /** Unit ID */
+  PACK_STRUCT_FLD_8(u8_t  unit_id[6]);
+  /** Jumpers */
+  PACK_STRUCT_FLD_8(u8_t  jumpers);
+  /** Test result */
+  PACK_STRUCT_FLD_8(u8_t  test_result);
+  /** Version number */
+  PACK_STRUCT_FIELD(u16_t version_number);
+  /** Period of statistics */
+  PACK_STRUCT_FIELD(u16_t period_of_statistics);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t number_of_crcs);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t number_of_alignment_errors);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t number_of_collisions);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t number_of_send_aborts);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u32_t number_of_good_sends);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u32_t number_of_good_receives);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t number_of_retransmits);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t number_of_no_resource_condition);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t number_of_free_command_blocks);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t total_number_of_command_blocks);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t max_total_number_of_command_blocks);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t number_of_pending_sessions);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t max_number_of_pending_sessions);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t max_total_sessions_possible);
+  /** Statistics */
+  PACK_STRUCT_FIELD(u16_t session_data_packet_size);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#ifdef NETBIOS_LWIP_NAME
+#define NETBIOS_LOCAL_NAME NETBIOS_LWIP_NAME
+#else
+static char netbiosns_local_name[NETBIOS_NAME_LEN];
+#define NETBIOS_LOCAL_NAME netbiosns_local_name
+#endif
+
+static struct udp_pcb *netbiosns_pcb;
+
+/** Decode a NetBIOS name (from packet to string) */
+static int
+netbiosns_name_decode(const char *name_enc, char *name_dec, int name_dec_len)
+{
+  const char *pname;
+  char       cname;
+  char       cnbname;
+  int        idx = 0;
+
+  LWIP_UNUSED_ARG(name_dec_len);
+
+  /* Start decoding netbios name. */
+  pname  = name_enc;
+  for (;;) {
+    /* Every two characters of the first level-encoded name
+     * turn into one character in the decoded name. */
+    cname = *pname;
+    if (cname == '\0') {
+      break;  /* no more characters */
+    }
+    if (cname == '.') {
+      break;  /* scope ID follows */
+    }
+    if (!lwip_isupper(cname)) {
+      /* Not legal. */
+      return -1;
+    }
+    cname -= 'A';
+    cnbname = cname << 4;
+    pname++;
+
+    cname = *pname;
+    if (!lwip_isupper(cname)) {
+      /* Not legal. */
+      return -1;
+    }
+    cname -= 'A';
+    cnbname |= cname;
+    pname++;
+
+    /* Do we have room to store the character? */
+    if (idx < NETBIOS_NAME_LEN) {
+      /* Yes - store the character. */
+      name_dec[idx++] = (cnbname != ' ' ? cnbname : '\0');
+    }
+  }
+
+  return 0;
+}
+
+#if 0 /* function currently unused */
+/** Encode a NetBIOS name (from string to packet) - currently unused because
+    we don't ask for names. */
+static int
+netbiosns_name_encode(char *name_enc, char *name_dec, int name_dec_len)
+{
+  char         *pname;
+  char          cname;
+  unsigned char ucname;
+  int           idx = 0;
+
+  /* Start encoding netbios name. */
+  pname = name_enc;
+
+  for (;;) {
+    /* Every two characters of the first level-encoded name
+     * turn into one character in the decoded name. */
+    cname = *pname;
+    if (cname == '\0') {
+      break;  /* no more characters */
+    }
+    if (cname == '.') {
+      break;  /* scope ID follows */
+    }
+    if ((cname < 'A' || cname > 'Z') && (cname < '0' || cname > '9')) {
+      /* Not legal. */
+      return -1;
+    }
+
+    /* Do we have room to store the character? */
+    if (idx >= name_dec_len) {
+      return -1;
+    }
+
+    /* Yes - store the character. */
+    ucname = cname;
+    name_dec[idx++] = ('A' + ((ucname >> 4) & 0x0F));
+    name_dec[idx++] = ('A' + ( ucname     & 0x0F));
+    pname++;
+  }
+
+  /* Fill with "space" coding */
+  for (; idx < name_dec_len - 1;) {
+    name_dec[idx++] = 'C';
+    name_dec[idx++] = 'A';
+  }
+
+  /* Terminate string */
+  name_dec[idx] = '\0';
+
+  return 0;
+}
+#endif /* 0 */
+
+/** NetBIOS Name service recv callback */
+static void
+netbiosns_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
+{
+  LWIP_UNUSED_ARG(arg);
+
+  /* if packet is valid */
+  if (p != NULL) {
+    char   netbios_name[NETBIOS_NAME_LEN + 1];
+    struct netbios_hdr          *netbios_hdr          = (struct netbios_hdr *)p->payload;
+    struct netbios_question_hdr *netbios_question_hdr = (struct netbios_question_hdr *)(netbios_hdr + 1);
+
+    /* is the packet long enough (we need the header in one piece) */
+    if (p->len < (sizeof(struct netbios_hdr) + sizeof(struct netbios_question_hdr))) {
+      /* packet too short */
+      pbuf_free(p);
+      return;
+    }
+    /* we only answer if we got a default interface */
+    if (netif_default != NULL) {
+      /* @todo: do we need to check answerRRs/authorityRRs/additionalRRs? */
+      /* if the packet is a NetBIOS name query question */
+      if (((netbios_hdr->flags & PP_NTOHS(NETB_HFLAG_OPCODE)) == PP_NTOHS(NETB_HFLAG_OPCODE_NAME_QUERY)) &&
+          ((netbios_hdr->flags & PP_NTOHS(NETB_HFLAG_RESPONSE)) == 0) &&
+          (netbios_hdr->questions == PP_NTOHS(1))) {
+        /* decode the NetBIOS name */
+        netbiosns_name_decode((char *)(netbios_question_hdr->encname), netbios_name, sizeof(netbios_name));
+        /* check the request type */
+        if (netbios_question_hdr->type == PP_HTONS(NETB_QTYPE_NB)) {
+          /* if the packet is for us */
+          if (lwip_strnicmp(netbios_name, NETBIOS_LOCAL_NAME, sizeof(NETBIOS_LOCAL_NAME)) == 0) {
+            struct pbuf *q;
+            struct netbios_resp *resp;
+
+            q = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct netbios_resp), PBUF_RAM);
+            if (q != NULL) {
+              resp = (struct netbios_resp *)q->payload;
+
+              /* prepare NetBIOS header response */
+              resp->resp_hdr.trans_id      = netbios_hdr->trans_id;
+              resp->resp_hdr.flags         = PP_HTONS(NETB_HFLAG_RESPONSE |
+                                                      NETB_HFLAG_OPCODE_NAME_QUERY |
+                                                      NETB_HFLAG_AUTHORATIVE |
+                                                      NETB_HFLAG_RECURS_DESIRED);
+              resp->resp_hdr.questions     = 0;
+              resp->resp_hdr.answerRRs     = PP_HTONS(1);
+              resp->resp_hdr.authorityRRs  = 0;
+              resp->resp_hdr.additionalRRs = 0;
+
+              /* prepare NetBIOS header datas */
+              MEMCPY( resp->resp_name.encname, netbios_question_hdr->encname, sizeof(netbios_question_hdr->encname));
+              resp->resp_name.nametype     = netbios_question_hdr->nametype;
+              resp->resp_name.type         = netbios_question_hdr->type;
+              resp->resp_name.cls          = netbios_question_hdr->cls;
+              resp->resp_name.ttl          = PP_HTONL(NETBIOS_NAME_TTL);
+              resp->resp_name.datalen      = PP_HTONS(sizeof(resp->resp_name.flags) + sizeof(resp->resp_name.addr));
+              resp->resp_name.flags        = PP_HTONS(NETB_NFLAG_NODETYPE_BNODE);
+              ip4_addr_copy(resp->resp_name.addr, *netif_ip4_addr(netif_default));
+
+              /* send the NetBIOS response */
+              udp_sendto(upcb, q, addr, port);
+
+              /* free the "reference" pbuf */
+              pbuf_free(q);
+            }
+          }
+#if LWIP_NETBIOS_RESPOND_NAME_QUERY
+        } else if (netbios_question_hdr->type == PP_HTONS(NETB_QTYPE_NBSTAT)) {
+          /* if the packet is for us or general query */
+          if (!lwip_strnicmp(netbios_name, NETBIOS_LOCAL_NAME, sizeof(NETBIOS_LOCAL_NAME)) ||
+              !lwip_strnicmp(netbios_name, "*", sizeof(NETBIOS_LOCAL_NAME))) {
+            /* general query - ask for our IP address */
+            struct pbuf *q;
+            struct netbios_answer *resp;
+
+            q = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct netbios_answer), PBUF_RAM);
+            if (q != NULL) {
+              /* buffer to which a response is compiled */
+              resp = (struct netbios_answer *) q->payload;
+
+              /* Init response to zero, especially the statistics fields */
+              memset(resp, 0, sizeof(*resp));
+
+              /* copy the query to the response ID */
+              resp->answer_hdr.trans_id        = netbios_hdr->trans_id;
+              /* acknowledgment of termination */
+              resp->answer_hdr.flags           = PP_HTONS(NETB_HFLAG_RESPONSE | NETB_HFLAG_OPCODE_NAME_QUERY | NETB_HFLAG_AUTHORATIVE);
+              /* resp->answer_hdr.questions       = PP_HTONS(0); done by memset() */
+              /* serial number of the answer */
+              resp->answer_hdr.answerRRs       = PP_HTONS(1);
+              /* resp->answer_hdr.authorityRRs    = PP_HTONS(0); done by memset() */
+              /* resp->answer_hdr.additionalRRs   = PP_HTONS(0); done by memset() */
+              /* we will copy the length of the station name */
+              resp->name_size                  = netbios_question_hdr->nametype;
+              /* we will copy the queried name */
+              MEMCPY(resp->query_name, netbios_question_hdr->encname, (NETBIOS_NAME_LEN * 2) + 1);
+              /* NBSTAT */
+              resp->packet_type                = PP_HTONS(0x21);
+              /* Internet name */
+              resp->cls                        = PP_HTONS(1);
+              /* resp->ttl                        = PP_HTONL(0); done by memset() */
+              resp->data_length                = PP_HTONS(sizeof(struct netbios_answer) - offsetof(struct netbios_answer, number_of_names));
+              resp->number_of_names            = 1;
+
+              /* make windows see us as workstation, not as a server */
+              memset(resp->answer_name, 0x20, NETBIOS_NAME_LEN - 1);
+              /* strlen is checked to be < NETBIOS_NAME_LEN during initialization */
+              MEMCPY(resp->answer_name, NETBIOS_LOCAL_NAME, strlen(NETBIOS_LOCAL_NAME));
+
+              /* b-node, unique, active */
+              resp->answer_name_flags          = PP_HTONS(NETB_NFLAG_NAME_IS_ACTIVE);
+
+              /* Set responder netif MAC address */
+              SMEMCPY(resp->unit_id, ip_current_input_netif()->hwaddr, sizeof(resp->unit_id));
+
+              udp_sendto(upcb, q, addr, port);
+              pbuf_free(q);
+            }
+          }
+#endif /* LWIP_NETBIOS_RESPOND_NAME_QUERY */
+        }
+      }
+    }
+    /* free the pbuf */
+    pbuf_free(p);
+  }
+}
+
+/**
+ * @ingroup netbiosns
+ * Init netbios responder
+ */
+void
+netbiosns_init(void)
+{
+  /* LWIP_ASSERT_CORE_LOCKED(); is checked by udp_new() */
+#ifdef NETBIOS_LWIP_NAME
+  LWIP_ASSERT("NetBIOS name is too long!", strlen(NETBIOS_LWIP_NAME) < NETBIOS_NAME_LEN);
+#endif
+
+  netbiosns_pcb = udp_new_ip_type(IPADDR_TYPE_ANY);
+  if (netbiosns_pcb != NULL) {
+    /* we have to be allowed to send broadcast packets! */
+    ip_set_option(netbiosns_pcb, SOF_BROADCAST);
+    udp_bind(netbiosns_pcb, IP_ANY_TYPE, LWIP_IANA_PORT_NETBIOS);
+    udp_recv(netbiosns_pcb, netbiosns_recv, netbiosns_pcb);
+  }
+}
+
+#ifndef NETBIOS_LWIP_NAME
+/**
+ * @ingroup netbiosns
+ * Set netbios name. ATTENTION: the hostname must be less than 15 characters!
+ *                              the NetBIOS name spec says the name MUST be upper case, so incoming name is forced into uppercase :-)
+ */
+void
+netbiosns_set_name(const char *hostname)
+{
+  size_t i;
+  size_t copy_len = strlen(hostname);
+  LWIP_ASSERT_CORE_LOCKED();
+  LWIP_ASSERT("NetBIOS name is too long!", copy_len < NETBIOS_NAME_LEN);
+  if (copy_len >= NETBIOS_NAME_LEN) {
+    copy_len = NETBIOS_NAME_LEN - 1;
+  }
+
+  /* make name into upper case */
+  for (i = 0; i < copy_len; i++ ) {
+    netbiosns_local_name[i] = (char)lwip_toupper(hostname[i]);
+  }
+  netbiosns_local_name[copy_len] = '\0';
+}
+#endif /* NETBIOS_LWIP_NAME */
+
+/**
+ * @ingroup netbiosns
+ * Stop netbios responder
+ */
+void
+netbiosns_stop(void)
+{
+  LWIP_ASSERT_CORE_LOCKED();
+  if (netbiosns_pcb != NULL) {
+    udp_remove(netbiosns_pcb);
+    netbiosns_pcb = NULL;
+  }
+}
+
+#endif /* LWIP_IPV4 && LWIP_UDP */