Re: [RFC v1 1/2] um: drivers: remove support for UML_NET_PCAP

From: Anton Ivanov
Date: Fri Dec 06 2019 - 02:23:54 EST

On 06/12/2019 02:01, Brendan Higgins wrote:
Remove support for UML_NET_PCAP. It is broken. When building with
libpcap installed, the build fails:

arch/um/drivers/pcap_user.c:35:12: error: conflicting types for âpcap_openâ
static int pcap_open(void *data)
^~~~~~~~~
In file included from /usr/include/pcap.h:43,
from arch/um/drivers/pcap_user.c:7:
/usr/include/pcap/pcap.h:859:18: note: previous declaration of âpcap_openâ was here
PCAP_API pcap_t *pcap_open(const char *source, int snaplen, int flags,
^~~~~~~~~

So it looks like this has probably been broken for some time.

In interest of trying to make allyesconfig work with UML, it is best
just to drop this.

Signed-off-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
---
arch/um/drivers/Kconfig | 16 -----
arch/um/drivers/Makefile | 17 +----
arch/um/drivers/pcap_kern.c | 113 -----------------------------
arch/um/drivers/pcap_user.c | 137 ------------------------------------
arch/um/drivers/pcap_user.h | 21 ------
5 files changed, 2 insertions(+), 302 deletions(-)
delete mode 100644 arch/um/drivers/pcap_kern.c
delete mode 100644 arch/um/drivers/pcap_user.c
delete mode 100644 arch/um/drivers/pcap_user.h

diff --git a/arch/um/drivers/Kconfig b/arch/um/drivers/Kconfig
index 388096fb45a25..98fead07c33de 100644
--- a/arch/um/drivers/Kconfig
+++ b/arch/um/drivers/Kconfig
@@ -291,22 +291,6 @@ config UML_NET_MCAST
exclusive). If you don't need to network UMLs say N to each of
the transports.
-config UML_NET_PCAP
- bool "pcap transport"
- depends on UML_NET
- help
- The pcap transport makes a pcap packet stream on the host look
- like an ethernet device inside UML. This is useful for making
- UML act as a network monitor for the host. You must have libcap
- installed in order to build the pcap transport into UML.
-
- For more information, see
- <http://user-mode-linux.sourceforge.net/old/networking.html> That site
- has examples of the UML command line to use to enable this option.
-
- If you intend to use UML as a network monitor for the host, say
- Y here. Otherwise, say N.
-
config UML_NET_SLIRP
bool "SLiRP transport"
depends on UML_NET
diff --git a/arch/um/drivers/Makefile b/arch/um/drivers/Makefile
index a290821e355c2..7548b18e77a27 100644
--- a/arch/um/drivers/Makefile
+++ b/arch/um/drivers/Makefile
@@ -3,9 +3,6 @@
# Copyright (C) 2000, 2002, 2003 Jeff Dike (jdike@xxxxxxxxxx)
#
-# pcap is broken in 2.5 because kbuild doesn't allow pcap.a to be linked
-# in to pcap.o
-
slip-objs := slip_kern.o slip_user.o
slirp-objs := slirp_kern.o slirp_user.o
daemon-objs := daemon_kern.o daemon_user.o
@@ -18,14 +15,9 @@ ubd-objs := ubd_kern.o ubd_user.o
port-objs := port_kern.o port_user.o
harddog-objs := harddog_kern.o harddog_user.o
-LDFLAGS_pcap.o := -r $(shell $(CC) $(KBUILD_CFLAGS) -print-file-name=libpcap.a)
-
LDFLAGS_vde.o := -r $(shell $(CC) $(CFLAGS) -print-file-name=libvdeplug.a)
-targets := pcap_kern.o pcap_user.o vde_kern.o vde_user.o
-
-$(obj)/pcap.o: $(obj)/pcap_kern.o $(obj)/pcap_user.o
- $(LD) -r -dp -o $@ $^ $(ld_flags)
+targets := vde_kern.o vde_user.o
$(obj)/vde.o: $(obj)/vde_kern.o $(obj)/vde_user.o
$(LD) -r -dp -o $@ $^ $(ld_flags)
@@ -34,9 +26,6 @@ $(obj)/vde.o: $(obj)/vde_kern.o $(obj)/vde_user.o
# object name, so nothing from the library gets linked.
#$(call if_changed,ld)
-# When the above is fixed, don't forget to add this too!
-#targets += $(obj)/pcap.o
-
obj-y := stdio_console.o fd.o chan_kern.o chan_user.o line.o
obj-$(CONFIG_SSL) += ssl.o
obj-$(CONFIG_STDERR_CONSOLE) += stderr_console.o
@@ -47,7 +36,6 @@ obj-$(CONFIG_UML_NET_DAEMON) += daemon.o
obj-$(CONFIG_UML_NET_VECTOR) += vector.o
obj-$(CONFIG_UML_NET_VDE) += vde.o
obj-$(CONFIG_UML_NET_MCAST) += umcast.o
-obj-$(CONFIG_UML_NET_PCAP) += pcap.o
obj-$(CONFIG_UML_NET) += net.o
obj-$(CONFIG_MCONSOLE) += mconsole.o
obj-$(CONFIG_MMAPPER) += mmapper_kern.o
@@ -63,8 +51,7 @@ obj-$(CONFIG_BLK_DEV_COW_COMMON) += cow_user.o
obj-$(CONFIG_UML_RANDOM) += random.o
obj-$(CONFIG_VIRTIO_UML) += virtio_uml.o
-# pcap_user.o must be added explicitly.
-USER_OBJS := fd.o null.o pty.o tty.o xterm.o slip_common.o pcap_user.o vde_user.o vector_user.o
+USER_OBJS := fd.o null.o pty.o tty.o xterm.o slip_common.o vde_user.o vector_user.o
CFLAGS_null.o = -DDEV_NULL=$(DEV_NULL_PATH)
include arch/um/scripts/Makefile.rules
diff --git a/arch/um/drivers/pcap_kern.c b/arch/um/drivers/pcap_kern.c
deleted file mode 100644
index cfe4cb17694cc..0000000000000
--- a/arch/um/drivers/pcap_kern.c
+++ /dev/null
@@ -1,113 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
- */
-
-#include <linux/init.h>
-#include <linux/netdevice.h>
-#include <net_kern.h>
-#include "pcap_user.h"
-
-struct pcap_init {
- char *host_if;
- int promisc;
- int optimize;
- char *filter;
-};
-
-void pcap_init(struct net_device *dev, void *data)
-{
- struct uml_net_private *pri;
- struct pcap_data *ppri;
- struct pcap_init *init = data;
-
- pri = netdev_priv(dev);
- ppri = (struct pcap_data *) pri->user;
- ppri->host_if = init->host_if;
- ppri->promisc = init->promisc;
- ppri->optimize = init->optimize;
- ppri->filter = init->filter;
-
- printk("pcap backend, host interface %s\n", ppri->host_if);
-}
-
-static int pcap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
-{
- return pcap_user_read(fd, skb_mac_header(skb),
- skb->dev->mtu + ETH_HEADER_OTHER,
- (struct pcap_data *) &lp->user);
-}
-
-static int pcap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
-{
- return -EPERM;
-}
-
-static const struct net_kern_info pcap_kern_info = {
- .init = pcap_init,
- .protocol = eth_protocol,
- .read = pcap_read,
- .write = pcap_write,
-};
-
-int pcap_setup(char *str, char **mac_out, void *data)
-{
- struct pcap_init *init = data;
- char *remain, *host_if = NULL, *options[2] = { NULL, NULL };
- int i;
-
- *init = ((struct pcap_init)
- { .host_if = "eth0",
- .promisc = 1,
- .optimize = 0,
- .filter = NULL });
-
- remain = split_if_spec(str, &host_if, &init->filter,
- &options[0], &options[1], mac_out, NULL);
- if (remain != NULL) {
- printk(KERN_ERR "pcap_setup - Extra garbage on "
- "specification : '%s'\n", remain);
- return 0;
- }
-
- if (host_if != NULL)
- init->host_if = host_if;
-
- for (i = 0; i < ARRAY_SIZE(options); i++) {
- if (options[i] == NULL)
- continue;
- if (!strcmp(options[i], "promisc"))
- init->promisc = 1;
- else if (!strcmp(options[i], "nopromisc"))
- init->promisc = 0;
- else if (!strcmp(options[i], "optimize"))
- init->optimize = 1;
- else if (!strcmp(options[i], "nooptimize"))
- init->optimize = 0;
- else {
- printk(KERN_ERR "pcap_setup : bad option - '%s'\n",
- options[i]);
- return 0;
- }
- }
-
- return 1;
-}
-
-static struct transport pcap_transport = {
- .list = LIST_HEAD_INIT(pcap_transport.list),
- .name = "pcap",
- .setup = pcap_setup,
- .user = &pcap_user_info,
- .kern = &pcap_kern_info,
- .private_size = sizeof(struct pcap_data),
- .setup_size = sizeof(struct pcap_init),
-};
-
-static int register_pcap(void)
-{
- register_transport(&pcap_transport);
- return 0;
-}
-
-late_initcall(register_pcap);
diff --git a/arch/um/drivers/pcap_user.c b/arch/um/drivers/pcap_user.c
deleted file mode 100644
index bbd20638788af..0000000000000
--- a/arch/um/drivers/pcap_user.c
+++ /dev/null
@@ -1,137 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
- */
-
-#include <errno.h>
-#include <pcap.h>
-#include <string.h>
-#include <asm/types.h>
-#include <net_user.h>
-#include "pcap_user.h"
-#include <um_malloc.h>
-
-#define PCAP_FD(p) (*(int *)(p))
-
-static int pcap_user_init(void *data, void *dev)
-{
- struct pcap_data *pri = data;
- pcap_t *p;
- char errors[PCAP_ERRBUF_SIZE];
-
- p = pcap_open_live(pri->host_if, ETH_MAX_PACKET + ETH_HEADER_OTHER,
- pri->promisc, 0, errors);
- if (p == NULL) {
- printk(UM_KERN_ERR "pcap_user_init : pcap_open_live failed - "
- "'%s'\n", errors);
- return -EINVAL;
- }
-
- pri->dev = dev;
- pri->pcap = p;
- return 0;
-}
-
-static int pcap_open(void *data)
-{
- struct pcap_data *pri = data;
- __u32 netmask;
- int err;
-
- if (pri->pcap == NULL)
- return -ENODEV;
-
- if (pri->filter != NULL) {
- err = dev_netmask(pri->dev, &netmask);
- if (err < 0) {
- printk(UM_KERN_ERR "pcap_open : dev_netmask failed\n");
- return -EIO;
- }
-
- pri->compiled = uml_kmalloc(sizeof(struct bpf_program),
- UM_GFP_KERNEL);
- if (pri->compiled == NULL) {
- printk(UM_KERN_ERR "pcap_open : kmalloc failed\n");
- return -ENOMEM;
- }
-
- err = pcap_compile(pri->pcap,
- (struct bpf_program *) pri->compiled,
- pri->filter, pri->optimize, netmask);
- if (err < 0) {
- printk(UM_KERN_ERR "pcap_open : pcap_compile failed - "
- "'%s'\n", pcap_geterr(pri->pcap));
- goto out;
- }
-
- err = pcap_setfilter(pri->pcap, pri->compiled);
- if (err < 0) {
- printk(UM_KERN_ERR "pcap_open : pcap_setfilter "
- "failed - '%s'\n", pcap_geterr(pri->pcap));
- goto out;
- }
- }
-
- return PCAP_FD(pri->pcap);
-
- out:
- kfree(pri->compiled);
- return -EIO;
-}
-
-static void pcap_remove(void *data)
-{
- struct pcap_data *pri = data;
-
- if (pri->compiled != NULL)
- pcap_freecode(pri->compiled);
-
- if (pri->pcap != NULL)
- pcap_close(pri->pcap);
-}
-
-struct pcap_handler_data {
- char *buffer;
- int len;
-};
-
-static void handler(u_char *data, const struct pcap_pkthdr *header,
- const u_char *packet)
-{
- int len;
-
- struct pcap_handler_data *hdata = (struct pcap_handler_data *) data;
-
- len = hdata->len < header->caplen ? hdata->len : header->caplen;
- memcpy(hdata->buffer, packet, len);
- hdata->len = len;
-}
-
-int pcap_user_read(int fd, void *buffer, int len, struct pcap_data *pri)
-{
- struct pcap_handler_data hdata = ((struct pcap_handler_data)
- { .buffer = buffer,
- .len = len });
- int n;
-
- n = pcap_dispatch(pri->pcap, 1, handler, (u_char *) &hdata);
- if (n < 0) {
- printk(UM_KERN_ERR "pcap_dispatch failed - %s\n",
- pcap_geterr(pri->pcap));
- return -EIO;
- }
- else if (n == 0)
- return 0;
- return hdata.len;
-}
-
-const struct net_user_info pcap_user_info = {
- .init = pcap_user_init,
- .open = pcap_open,
- .close = NULL,
- .remove = pcap_remove,
- .add_address = NULL,
- .delete_address = NULL,
- .mtu = ETH_MAX_PACKET,
- .max_packet = ETH_MAX_PACKET + ETH_HEADER_OTHER,
-};
diff --git a/arch/um/drivers/pcap_user.h b/arch/um/drivers/pcap_user.h
deleted file mode 100644
index 216246f5f09bd..0000000000000
--- a/arch/um/drivers/pcap_user.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Copyright (C) 2002 Jeff Dike (jdike@xxxxxxxxxx)
- */
-
-#include <net_user.h>
-
-struct pcap_data {
- char *host_if;
- int promisc;
- int optimize;
- char *filter;
- void *compiled;
- void *pcap;
- void *dev;
-};
-
-extern const struct net_user_info pcap_user_info;
-
-extern int pcap_user_read(int fd, void *buf, int len, struct pcap_data *pri);
-


1. There is a proposed patch for the build system to fix it.

2. We should be removing all old drivers and replacing them with the vector ones.

--
Anton R. Ivanov
Cambridgegreys Limited. Registered in England. Company Number 10273661
https://www.cambridgegreys.com/