[Qemu-devel] [PATCH] networking using libpcap

[Ulrich Hecht <uli@suse.de>]

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Hi!

I just discovered this patch

http://lists.freebsd.org/pipermail/freebsd-emulation/2007-February/003107.html

that implements network access using libpcap. Works perfect for me and 
allows access to the local Ethernet right out of the box, very much 
unlike tap and bridging. The attached version applies to trunk.

CU
Uli

Index: Makefile.target
===================================================================
--- Makefile.target	(revision 4820)
+++ Makefile.target	(working copy)
@@ -619,6 +619,9 @@
 ifdef CONFIG_SLIRP
 CPPFLAGS+=-I$(SRC_PATH)/slirp
 endif
+ifdef CONFIG_PCAP
+LIBS+=-lpcap
+endif
 
 LIBS+=$(AIOLIBS)
 # specific flags are needed for non soft mmu emulator
Index: vl.c
===================================================================
--- vl.c	(revision 4820)
+++ vl.c	(working copy)
@@ -102,6 +102,10 @@
 int inet_aton(const char *cp, struct in_addr *ia);
 #endif
 
+#if defined(CONFIG_PCAP)
+#include <pcap.h>
+#endif
+
 #if defined(CONFIG_SLIRP)
 #include "libslirp.h"
 #endif
@@ -4094,6 +4098,104 @@
 
 #endif /* CONFIG_SLIRP */
 
+#if defined(CONFIG_PCAP)
+
+typedef struct PCAPState {
+    VLANClientState *vc;
+    pcap_t *handle;
+} PCAPState;
+
+static void pcap_receive(void *opaque, const uint8_t *buf, int size)
+{
+    PCAPState *s = (PCAPState *)opaque;
+
+    pcap_sendpacket(s->handle, (u_char*)buf, size);
+}
+
+static void pcap_callback(u_char *user, struct pcap_pkthdr *phdr, u_char 
*pdata)
+{
+    VLANClientState *vc = (VLANClientState *)user;
+
+    qemu_send_packet(vc, pdata, phdr->len);
+}
+
+static void pcap_send(void *opaque)
+{
+    PCAPState *s = (PCAPState *)opaque;
+
+    pcap_dispatch(s->handle, 1, (pcap_handler)&pcap_callback, (u_char 
*)s->vc);
+}
+
+static int net_pcap_init(VLANState *vlan, char *ifname)
+{
+    PCAPState *s;
+    char errbuf[PCAP_ERRBUF_SIZE];
+    int fd;
+
+    s = qemu_mallocz(sizeof(PCAPState));
+    if (!s)
+        return -1;
+
+    if (ifname == NULL && (ifname = pcap_lookupdev(errbuf)) == NULL) {
+	fprintf(stderr, "qemu: pcap_lookupdev: %s\n", errbuf);
+	goto fail;
+    }
+
+    /* Attempt to connect device. */
+    s->handle = (void*)pcap_open_live(ifname, 65535, 1, 0, errbuf);
+    if (!s->handle) {
+	fprintf(stderr, "qemu: pcap_open_live: %s\n", errbuf);
+	goto fail;
+    }
+
+    /* Check non-blocking mode. */
+    if (pcap_setnonblock(s->handle, 1, errbuf) < 0) {
+	fprintf(stderr, "qemu: pcap_setnonblock: %s\n", errbuf);
+	goto fail;
+    }
+
+#if defined(BIOCSHDRCMPLT)
+    /*
+     * Tell the kernel that the header is fully-formed when it gets it.
+     * This is required in order to fake the src address.
+     */
+    {
+	unsigned int one = 1;
+	ioctl(pcap_fileno(s->handle), BIOCSHDRCMPLT, &one);
+    }
+#endif /* BIOCSHDRCMPLT */
+
+#if defined(BIOCIMMEDIATE)
+    /*
+     * Tell the kernel that the packet has to be processed immediately.
+     */
+    {
+	unsigned int one = 1;
+	ioctl(pcap_fileno(s->handle), BIOCIMMEDIATE, &one);
+    }
+#endif /* BIOCIMMEDIATE */
+
+    s->vc = qemu_new_vlan_client(vlan, pcap_receive, NULL, s);
+    snprintf(s->vc->info_str, sizeof(s->vc->info_str), "pcap 
redirector");
+    if ((fd = pcap_get_selectable_fd(s->handle)) < 0) {
+	fprintf(stderr, "qemu: pcap_get_selectable_fd failed\n");
+	goto fail;
+    }
+    qemu_set_fd_handler(fd, pcap_send, NULL, s);
+
+    return 0;
+
+fail:
+    if (s) {
+	if (s->handle)
+	    pcap_close(s->handle);
+	qemu_free(s);
+    }
+
+    return -1;
+}
+#endif /* CONFIG_PCAP */
+
 #if !defined(_WIN32)
 
 typedef struct TAPState {
@@ -4978,6 +5080,15 @@
         ret = net_slirp_init(vlan);
     } else
 #endif
+#ifdef CONFIG_PCAP
+    if (!strcmp(device, "pcap")) {
+	char ifname[64];
+	if (get_param_value(ifname, sizeof(ifname), "ifname", p) <= 0)
+	    ret = net_pcap_init(vlan, NULL);
+	else
+	    ret = net_pcap_init(vlan, ifname);
+    } else
+#endif
 #ifdef _WIN32
     if (!strcmp(device, "tap")) {
         char ifname[64];
@@ -7381,6 +7492,10 @@
            "                connect the user mode network stack to 
VLAN 'n' and send\n"
            "                hostname 'host' to DHCP clients\n"
 #endif
+#ifdef CONFIG_PCAP
+           "-net pcap[,vlan=n][,ifname=name]\n"
+           "                connect the host network interface using 
PCAP to VLAN 'n'\n"
+#endif
 #ifdef _WIN32
            "-net tap[,vlan=n],ifname=name\n"
            "                connect the host TAP network interface to 
VLAN 'n'\n"
Index: configure
===================================================================
--- configure	(revision 4820)
+++ configure	(working copy)
@@ -89,6 +89,7 @@
 EXESUF=""
 gdbstub="yes"
 slirp="yes"
+pcap="yes"
 fmod_lib=""
 fmod_inc=""
 vnc_tls="yes"
@@ -280,6 +281,8 @@
   ;;
   --disable-slirp) slirp="no"
   ;;
+  --disable-pcap) pcap="no"
+  ;;
   --disable-kqemu) kqemu="no"
   ;;
   --disable-brlapi) brlapi="no"
@@ -1032,6 +1035,10 @@
   echo "CONFIG_SLIRP=yes" >> $config_mak
   echo "#define CONFIG_SLIRP 1" >> $config_h
 fi
+if test "$pcap" = "yes" ; then
+  echo "CONFIG_PCAP=yes" >> $config_mak
+  echo "#define CONFIG_PCAP 1" >> $config_h
+fi
 for card in $audio_card_list; do
     def=CONFIG_`echo $card | tr '[:lower:]' '[:upper:]'`
     echo "$def=yes" >> $config_mak


-- 
SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg)

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Index: Makefile.target
===================================================================
--- Makefile.target	(revision 4820)
+++ Makefile.target	(working copy)
@@ -619,6 +619,9 @@
 ifdef CONFIG_SLIRP
 CPPFLAGS+=-I$(SRC_PATH)/slirp
 endif
+ifdef CONFIG_PCAP
+LIBS+=-lpcap
+endif
 
 LIBS+=$(AIOLIBS)
 # specific flags are needed for non soft mmu emulator
Index: vl.c
===================================================================
--- vl.c	(revision 4820)
+++ vl.c	(working copy)
@@ -102,6 +102,10 @@
 int inet_aton(const char *cp, struct in_addr *ia);
 #endif
 
+#if defined(CONFIG_PCAP)
+#include <pcap.h>
+#endif
+
 #if defined(CONFIG_SLIRP)
 #include "libslirp.h"
 #endif
@@ -4094,6 +4098,104 @@
 
 #endif /* CONFIG_SLIRP */
 
+#if defined(CONFIG_PCAP)
+
+typedef struct PCAPState {
+    VLANClientState *vc;
+    pcap_t *handle;
+} PCAPState;
+
+static void pcap_receive(void *opaque, const uint8_t *buf, int size)
+{
+    PCAPState *s = (PCAPState *)opaque;
+
+    pcap_sendpacket(s->handle, (u_char*)buf, size);
+}
+
+static void pcap_callback(u_char *user, struct pcap_pkthdr *phdr, u_char *pdata)
+{
+    VLANClientState *vc = (VLANClientState *)user;
+
+    qemu_send_packet(vc, pdata, phdr->len);
+}
+
+static void pcap_send(void *opaque)
+{
+    PCAPState *s = (PCAPState *)opaque;
+
+    pcap_dispatch(s->handle, 1, (pcap_handler)&pcap_callback, (u_char *)s->vc);
+}
+
+static int net_pcap_init(VLANState *vlan, char *ifname)
+{
+    PCAPState *s;
+    char errbuf[PCAP_ERRBUF_SIZE];
+    int fd;
+
+    s = qemu_mallocz(sizeof(PCAPState));
+    if (!s)
+        return -1;
+
+    if (ifname == NULL && (ifname = pcap_lookupdev(errbuf)) == NULL) {
+	fprintf(stderr, "qemu: pcap_lookupdev: %s\n", errbuf);
+	goto fail;
+    }
+
+    /* Attempt to connect device. */
+    s->handle = (void*)pcap_open_live(ifname, 65535, 1, 0, errbuf);
+    if (!s->handle) {
+	fprintf(stderr, "qemu: pcap_open_live: %s\n", errbuf);
+	goto fail;
+    }
+
+    /* Check non-blocking mode. */
+    if (pcap_setnonblock(s->handle, 1, errbuf) < 0) {
+	fprintf(stderr, "qemu: pcap_setnonblock: %s\n", errbuf);
+	goto fail;
+    }
+
+#if defined(BIOCSHDRCMPLT)
+    /*
+     * Tell the kernel that the header is fully-formed when it gets it.
+     * This is required in order to fake the src address.
+     */
+    {
+	unsigned int one = 1;
+	ioctl(pcap_fileno(s->handle), BIOCSHDRCMPLT, &one);
+    }
+#endif /* BIOCSHDRCMPLT */
+
+#if defined(BIOCIMMEDIATE)
+    /*
+     * Tell the kernel that the packet has to be processed immediately.
+     */
+    {
+	unsigned int one = 1;
+	ioctl(pcap_fileno(s->handle), BIOCIMMEDIATE, &one);
+    }
+#endif /* BIOCIMMEDIATE */
+
+    s->vc = qemu_new_vlan_client(vlan, pcap_receive, NULL, s);
+    snprintf(s->vc->info_str, sizeof(s->vc->info_str), "pcap redirector");
+    if ((fd = pcap_get_selectable_fd(s->handle)) < 0) {
+	fprintf(stderr, "qemu: pcap_get_selectable_fd failed\n");
+	goto fail;
+    }
+    qemu_set_fd_handler(fd, pcap_send, NULL, s);
+
+    return 0;
+
+fail:
+    if (s) {
+	if (s->handle)
+	    pcap_close(s->handle);
+	qemu_free(s);
+    }
+
+    return -1;
+}
+#endif /* CONFIG_PCAP */
+
 #if !defined(_WIN32)
 
 typedef struct TAPState {
@@ -4978,6 +5080,15 @@
         ret = net_slirp_init(vlan);
     } else
 #endif
+#ifdef CONFIG_PCAP
+    if (!strcmp(device, "pcap")) {
+	char ifname[64];
+	if (get_param_value(ifname, sizeof(ifname), "ifname", p) <= 0)
+	    ret = net_pcap_init(vlan, NULL);
+	else
+	    ret = net_pcap_init(vlan, ifname);
+    } else
+#endif
 #ifdef _WIN32
     if (!strcmp(device, "tap")) {
         char ifname[64];
@@ -7381,6 +7492,10 @@
            "                connect the user mode network stack to VLAN 'n' and send\n"
            "                hostname 'host' to DHCP clients\n"
 #endif
+#ifdef CONFIG_PCAP
+           "-net pcap[,vlan=n][,ifname=name]\n"
+           "                connect the host network interface using PCAP to VLAN 'n'\n"
+#endif
 #ifdef _WIN32
            "-net tap[,vlan=n],ifname=name\n"
            "                connect the host TAP network interface to VLAN 'n'\n"
Index: configure
===================================================================
--- configure	(revision 4820)
+++ configure	(working copy)
@@ -89,6 +89,7 @@
 EXESUF=""
 gdbstub="yes"
 slirp="yes"
+pcap="yes"
 fmod_lib=""
 fmod_inc=""
 vnc_tls="yes"
@@ -280,6 +281,8 @@
   ;;
   --disable-slirp) slirp="no"
   ;;
+  --disable-pcap) pcap="no"
+  ;;
   --disable-kqemu) kqemu="no"
   ;;
   --disable-brlapi) brlapi="no"
@@ -1032,6 +1035,10 @@
   echo "CONFIG_SLIRP=yes" >> $config_mak
   echo "#define CONFIG_SLIRP 1" >> $config_h
 fi
+if test "$pcap" = "yes" ; then
+  echo "CONFIG_PCAP=yes" >> $config_mak
+  echo "#define CONFIG_PCAP 1" >> $config_h
+fi
 for card in $audio_card_list; do
     def=CONFIG_`echo $card | tr '[:lower:]' '[:upper:]'`
     echo "$def=yes" >> $config_mak