Add mip-pcap example

.github/workflows/test.yml

@@ -27,7 +27,7 @@ jobs:
     steps:
     - uses: actions/checkout@v3
     - name: Install packages
-      run: sudo apt-get install libmbedtls-dev
+      run: sudo apt-get install libmbedtls-dev libpcap-dev
     - name: examples
       run: make clean examples
   macos:

examples/mip-pcap/Makefile

@@ -0,0 +1,13 @@
+PROG ?= example
+DEFS ?= -DMG_ENABLE_LINES=1 -DMG_ENABLE_MIP=1 -DMG_ENABLE_SOCKET=0 -DMG_ENABLE_WINSOCK=0 -I../..
+CFLAGS ?= -W -Wall
+LIBS ?= -lpcap
+
+all: $(PROG)
+	$(RUN) ./$(PROG) $(ARGS)
+
+$(PROG): main.c
+	$(CC) main.c ../../mongoose.c $(CFLAGS) $(DEFS) -o $(PROG) $(LIBS)
+
+clean:
+	rm -rf $(PROG) *.o *.dSYM *.gcov *.gcno *.gcda *.obj *.exe *.ilk *.pdb

examples/mip-pcap/main.c

@@ -0,0 +1,132 @@
+// Copyright (c) 2022 Cesanta Software Limited
+// All rights reserved
+//
+// SNTP example using MIP and pcap driver
+
+#include <pcap.h>
+#include "mongoose.h"
+
+static struct mg_connection *s_sntp_conn = NULL;
+
+static int s_signo;
+void signal_handler(int signo) {
+  s_signo = signo;
+}
+
+// SNTP client callback
+static void sfn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
+  if (ev == MG_EV_SNTP_TIME) {
+    int64_t t = *(int64_t *) ev_data;
+    MG_INFO(("Got SNTP time: %lld ms from epoch", t));
+  } else if (ev == MG_EV_CLOSE) {
+    s_sntp_conn = NULL;
+  }
+  (void) fn_data, (void) c;
+}
+
+// Called every 5 seconds. Increase that for production case.
+static void timer_fn(void *arg) {
+  struct mg_mgr *mgr = (struct mg_mgr *) arg;
+  if (s_sntp_conn == NULL) s_sntp_conn = mg_sntp_connect(mgr, NULL, sfn, NULL);
+  if (s_sntp_conn != NULL) mg_sntp_request(s_sntp_conn);
+}
+
+static int fail(const char *fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  vfprintf(stderr, fmt, ap);
+  va_end(ap);
+  return EXIT_FAILURE;
+}
+
+static size_t pcap_tx(const void *data, size_t len, void *userdata) {
+  int res = pcap_inject((pcap_t *) userdata, data, len);
+  if (res == PCAP_ERROR) {
+    MG_ERROR(("pcap_inject: %d", res));
+  }
+  return len;
+}
+
+static bool pcap_status(void *userdata) {
+  return userdata ? true : false;
+}
+
+static size_t pcap_rx(void *buf, size_t len, void *userdata) {
+  size_t received = 0;
+  struct pcap_pkthdr *hdr = NULL;
+  const unsigned char *pkt = NULL;
+  if (pcap_next_ex((pcap_t *) userdata, &hdr, &pkt) == 1) {
+    received = hdr->len < len ? hdr->len : len;
+    memcpy(buf, pkt, received);
+  }
+  return received;
+}
+
+int main(int argc, char *argv[]) {
+  const char *iface = "lo0";              // Network iface
+  const char *mac = "aa:bb:cc:01:02:03";  // MAC address
+  const char *bpf = NULL;  // "host x.x.x.x or ether host ff:ff:ff:ff:ff:ff";
+  char errbuf[PCAP_ERRBUF_SIZE] = "";
+
+  struct mg_mgr mgr;  // Event manager
+  mg_mgr_init(&mgr);  // Initialise event manager
+  mg_log_set("3");    // Set debug log level
+  mg_timer_add(&mgr, 3000, MG_TIMER_REPEAT | MG_TIMER_RUN_NOW, timer_fn, &mgr);
+
+  // Parse options
+  for (int i = 1; i < argc; i++) {
+    if (strcmp(argv[i], "-i") == 0 && i + 1 < argc) {
+      iface = argv[++i];
+    } else if (strcmp(argv[i], "-mac") == 0 && i + 1 < argc) {
+      mac = argv[++i];
+    } else if (strcmp(argv[i], "-bpf") == 0 && i + 1 < argc) {
+      bpf = argv[++i];
+    } else {
+      return fail("unknown option %s", argv[i]);
+    }
+  }
+
+  // Open network interface
+  pcap_t *ph = pcap_open_live(iface, 0xffff, 1, 1, errbuf);
+  if (ph == NULL) {
+    pcap_if_t *devs, *d;
+    MG_ERROR(("Failed to open interface %s. Available interfaces:", iface));
+    if (pcap_findalldevs(&devs, errbuf) == 0) {
+      for (d = devs; d != NULL; d = d->next) {
+        MG_ERROR(("%s (%s)", d->name, d->description ? d->description : ""));
+      }
+      pcap_freealldevs(devs);
+    }
+    fail("pcap_open_live: %s\n", errbuf);
+  }
+  pcap_setnonblock(ph, 1, errbuf);
+  // Apply BPF to reduce noise. Let in only broadcasts and our own traffic
+  if (bpf != NULL) {
+    struct bpf_program bpfp;
+    if (pcap_compile(ph, &bpfp, bpf, 1, 0)) fail("compile \n");
+    pcap_setfilter(ph, &bpfp);
+    pcap_freecode(&bpfp);
+  }
+  MG_INFO(("Opened interface %s\n", iface));
+
+  signal(SIGINT, signal_handler);
+  signal(SIGTERM, signal_handler);
+
+  struct mip_ipcfg ipcfg = {.ip = 0, .mask = 0, .gw = 0};
+  sscanf(mac, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx", &ipcfg.mac[0], &ipcfg.mac[1],
+         &ipcfg.mac[2], &ipcfg.mac[3], &ipcfg.mac[4], &ipcfg.mac[5]);
+
+  struct mip_driver driver = {
+      .data = ph, .tx = pcap_tx, .status = pcap_status, .rx = pcap_rx};
+
+  mip_init(&mgr, &ipcfg, &driver);
+  MG_INFO(("Init done, starting main loop"));
+
+  while (s_signo == 0) mg_mgr_poll(&mgr, 1);  // Infinite event loop
+
+  mg_mgr_free(&mgr);
+  pcap_close(ph);
+  printf("Exiting on signal %d\n", s_signo);
+
+  return 0;
+}