port: fix pcap support with meson

[ upstream commit 268fa58]

The meson build was missing the define to enable pcap port support if
libpcap (development) package was found on the build platform. Rather than
duplicating the checks for libpcap found in the pcap net PMD build file, we
can move the checks to the top-level config directory and reference the
RTE_PCAP_PORT setting elsewhere in the build.

Bugzilla ID: 351
Fixes: 5b9656b ("lib: build with meson")

Reported-by: Cristian Bidea <cristian.bidea@keysight.com>
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Tested-by: Cristian Bidea <cristian.bidea@keysight.com>

config/meson.build

@@ -89,6 +89,19 @@ if host_machine.system() == 'linux' and cc.find_library('bsd',
 	dpdk_extra_ldflags += '-lbsd'
 endif
 
+# check for pcap
+pcap_dep = dependency('pcap', required: false)
+if pcap_dep.found()
+	# pcap got a pkg-config file only in 1.9.0 and before that meson uses
+	# an internal pcap-config finder, which is not compatible with
+	# cross-compilation, so try to fallback to find_library
+	pcap_dep = cc.find_library('pcap', 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'
+endif
+
 # add -include rte_config to cflags
 add_project_arguments('-include', 'rte_config.h', language: 'c')
 

drivers/net/pcap/meson.build

@@ -1,11 +1,9 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2017 Intel Corporation
 
-pcap_dep = cc.find_library('pcap', required: false)
-if pcap_dep.found() and cc.has_header('pcap.h', dependencies: pcap_dep)
-	build = true
-else
+if not dpdk_conf.has('RTE_PORT_PCAP')
 	build = false
+	reason = 'missing dependency, "libpcap"'
 endif
 sources = files('rte_eth_pcap.c')
 ext_deps += pcap_dep

lib/librte_port/meson.build

@@ -23,6 +23,10 @@ headers = files(
 	'rte_port_sym_crypto.h')
 deps += ['ethdev', 'sched', 'ip_frag', 'cryptodev']
 
+if dpdk_conf.has('RTE_PORT_PCAP')
+	ext_deps += pcap_dep # dependency provided in config/meson.build
+endif
+
 if dpdk_conf.has('RTE_LIBRTE_KNI')
 	sources += files('rte_port_kni.c')
 	headers += files('rte_port_kni.h')