net/pcap: build on Windows

Implement OS-dependent functions and enable build for Windows.
Account for different library name in Windows libpcap distributions.

Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Acked-by: Tyler Retzlaff <roretzla@linux.microsoft.com>

config/meson.build

@@ -180,13 +180,14 @@ endif
 
 # check for pcap
 pcap_dep = dependency('libpcap', required: false, method: 'pkg-config')
+pcap_lib = is_windows ? 'wpcap' : 'pcap'
 if not pcap_dep.found()
     # pcap got a pkg-config file only in 1.9.0
-    pcap_dep = cc.find_library('pcap', required: false)
+    pcap_dep = cc.find_library(pcap_lib, required: false)
 endif
 if pcap_dep.found() and cc.has_header('pcap.h', dependencies: pcap_dep)
     dpdk_conf.set('RTE_PORT_PCAP', 1)
-    dpdk_extra_ldflags += '-lpcap'
+    dpdk_extra_ldflags += '-l@0@'.format(pcap_lib)
 endif
 
 # for clang 32-bit compiles we need libatomic for 64-bit atomic ops

doc/guides/rel_notes/release_21_05.rst

@@ -177,6 +177,10 @@ New Features
 
 * **Enabled vmxnet3 PMD on Windows.**
 
+* **Enabled libpcap-based PMD on Windows.**
+
+   A libpcap distribution, such as Npcap or WinPcap, is required to run the PMD.
+
 * **Updated the AF_XDP driver.**
 
   * Added support for preferred busy polling.

drivers/net/pcap/meson.build

@@ -1,18 +1,17 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2017 Intel Corporation
 
-if is_windows
-    build = false
-    reason = 'not supported on Windows'
-    subdir_done()
-endif
-
 if not dpdk_conf.has('RTE_PORT_PCAP')
     build = false
     reason = 'missing dependency, "libpcap"'
 endif
+
 sources = files(
         'pcap_ethdev.c',
         'pcap_osdep_@0@.c'.format(exec_env),
 )
+
 ext_deps += pcap_dep
+if is_windows
+    ext_deps += cc.find_library('iphlpapi', required: true)
+endif

drivers/net/pcap/pcap_ethdev.c

@@ -16,6 +16,7 @@
 #include <rte_mbuf.h>
 #include <rte_mbuf_dyn.h>
 #include <rte_bus_vdev.h>
+#include <rte_os_shim.h>
 
 #include "pcap_osdep.h"
 
@@ -142,10 +143,6 @@ static struct rte_eth_link pmd_link = {
 
 RTE_LOG_REGISTER(eth_pcap_logtype, pmd.net.pcap, NOTICE);
 
-#define PMD_LOG(level, fmt, args...) \
-	rte_log(RTE_LOG_ ## level, eth_pcap_logtype, \
-		"%s(): " fmt "\n", __func__, ##args)
-
 static struct queue_missed_stat*
 queue_missed_stat_update(struct rte_eth_dev *dev, unsigned int qid)
 {

drivers/net/pcap/pcap_osdep.h

@@ -7,6 +7,11 @@
 
 #include <rte_ether.h>
 
+#define PMD_LOG(level, fmt, args...) \
+	rte_log(RTE_LOG_ ## level, eth_pcap_logtype, \
+		"%s(): " fmt "\n", __func__, ##args)
+extern int eth_pcap_logtype;
+
 int osdep_iface_index_get(const char *name);
 int osdep_iface_mac_get(const char *name, struct rte_ether_addr *mac);
 

drivers/net/pcap/pcap_osdep_windows.c

@@ -0,0 +1,118 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (c) 2021 Dmitry Kozlyuk
+ */
+
+#include <winsock2.h>
+#include <iphlpapi.h>
+#include <strsafe.h>
+
+#include "pcap_osdep.h"
+
+/*
+ * Given a device name like "\Device\NPF_{GUID}" extract the "{GUID}" part.
+ * Return NULL if "{GUID}" part is not found.
+ */
+static const char *
+iface_guid(const char *name)
+{
+	static const size_t GUID_LENGTH = 32 + 4; /* 16 hex bytes + 4 dashes */
+
+	const char *ob, *cb;
+
+	ob = strchr(name, '{');
+	if (ob == NULL)
+		return NULL;
+
+	cb = strchr(ob, '}');
+	if (cb == NULL || cb - ob != GUID_LENGTH + 1) /* + 1 opening '{' */
+		return NULL;
+
+	return ob;
+}
+
+/*
+ * libpcap takes device names like "\Device\NPF_{GUID}",
+ * GetAdapterIndex() takes interface names like "\DEVICE\TCPIP_{GUID}".
+ * Try to convert, fall back to original device name.
+ */
+int
+osdep_iface_index_get(const char *device_name)
+{
+	WCHAR adapter_name[MAX_ADAPTER_NAME_LENGTH];
+	const char *guid;
+	ULONG index;
+	DWORD ret;
+
+	guid = iface_guid(device_name);
+	if (guid != NULL)
+		StringCbPrintfW(adapter_name, sizeof(adapter_name),
+			L"\\DEVICE\\TCPIP_%S", guid);
+	else
+		StringCbPrintfW(adapter_name, sizeof(adapter_name),
+			L"%S", device_name);
+
+	ret = GetAdapterIndex(adapter_name, &index);
+	if (ret != NO_ERROR) {
+		PMD_LOG(ERR, "GetAdapterIndex(%S) = %lu\n", adapter_name, ret);
+		return -1;
+	}
+
+	return index;
+}
+
+/*
+ * libpcap takes device names like "\Device\NPF_{GUID}",
+ * GetAdaptersAddresses() returns names in "{GUID}" form.
+ * Try to extract GUID from device name, fall back to original device name.
+ */
+int
+osdep_iface_mac_get(const char *device_name, struct rte_ether_addr *mac)
+{
+	IP_ADAPTER_ADDRESSES *info = NULL, *cur = NULL;
+	ULONG size, sys_ret;
+	const char *adapter_name;
+	int ret = -1;
+
+	sys_ret = GetAdaptersAddresses(AF_UNSPEC, 0, NULL, NULL, &size);
+	if (sys_ret != ERROR_BUFFER_OVERFLOW) {
+		PMD_LOG(ERR, "GetAdapterAddresses() = %lu, expected %lu\n",
+			sys_ret, ERROR_BUFFER_OVERFLOW);
+		return -1;
+	}
+
+	info = (IP_ADAPTER_ADDRESSES *)malloc(size);
+	if (info == NULL) {
+		PMD_LOG(ERR, "Cannot allocate adapter address info\n");
+		return -1;
+	}
+
+	sys_ret = GetAdaptersAddresses(AF_UNSPEC, 0, NULL, info, &size);
+	if (sys_ret != ERROR_SUCCESS) {
+		PMD_LOG(ERR, "GetAdapterAddresses() = %lu\n", sys_ret);
+		free(info);
+		return -1;
+	}
+
+	adapter_name = iface_guid(device_name);
+	if (adapter_name == NULL)
+		adapter_name = device_name;
+
+	for (cur = info; cur != NULL; cur = cur->Next) {
+		if (strcmp(cur->AdapterName, adapter_name) == 0) {
+			if (cur->PhysicalAddressLength != RTE_ETHER_ADDR_LEN) {
+				PMD_LOG(ERR, "Physical address length: want %u, got %lu",
+					RTE_ETHER_ADDR_LEN,
+					cur->PhysicalAddressLength);
+				break;
+			}
+
+			memcpy(mac->addr_bytes, cur->PhysicalAddress,
+				RTE_ETHER_ADDR_LEN);
+			ret = 0;
+			break;
+		}
+	}
+
+	free(info);
+	return ret;
+}