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linux/net/bpfilter/Makefile

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net: add skeleton of bpfilter kernel module bpfilter.ko consists of bpfilter_kern.c (normal kernel module code) and user mode helper code that is embedded into bpfilter.ko The steps to build bpfilter.ko are the following: - main.c is compiled by HOSTCC into the bpfilter_umh elf executable file - with quite a bit of objcopy and Makefile magic the bpfilter_umh elf file is converted into bpfilter_umh.o object file with _binary_net_bpfilter_bpfilter_umh_start and _end symbols Example: $ nm ./bld_x64/net/bpfilter/bpfilter_umh.o 0000000000004cf8 T _binary_net_bpfilter_bpfilter_umh_end 0000000000004cf8 A _binary_net_bpfilter_bpfilter_umh_size 0000000000000000 T _binary_net_bpfilter_bpfilter_umh_start - bpfilter_umh.o and bpfilter_kern.o are linked together into bpfilter.ko bpfilter_kern.c is a normal kernel module code that calls the fork_usermode_blob() helper to execute part of its own data as a user mode process. Notice that _binary_net_bpfilter_bpfilter_umh_start - end is placed into .init.rodata section, so it's freed as soon as __init function of bpfilter.ko is finished. As part of __init the bpfilter.ko does first request/reply action via two unix pipe provided by fork_usermode_blob() helper to make sure that umh is healthy. If not it will kill it via pid. Later bpfilter_process_sockopt() will be called from bpfilter hooks in get/setsockopt() to pass iptable commands into umh via bpfilter.ko If admin does 'rmmod bpfilter' the __exit code bpfilter.ko will kill umh as well. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-22 02:22:30 +00:00
# SPDX-License-Identifier: GPL-2.0
#
# Makefile for the Linux BPFILTER layer.
#
hostprogs-y := bpfilter_umh
bpfilter_umh-objs := main.o
bpfilter: fix a build err gcc-7.3.0 report following err: HOSTCC net/bpfilter/main.o In file included from net/bpfilter/main.c:9:0: ./include/uapi/linux/bpf.h:12:10: fatal error: linux/bpf_common.h: No such file or directory #include <linux/bpf_common.h> remove it by adding a include path. Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-25 10:17:57 +00:00
HOSTCFLAGS += -I. -Itools/include/ -Itools/include/uapi
bpfilter: switch to CC from HOSTCC check that CC can build executables and use that compiler instead of HOSTCC Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-05 02:53:41 +00:00
HOSTCC := $(CC)
net: add skeleton of bpfilter kernel module bpfilter.ko consists of bpfilter_kern.c (normal kernel module code) and user mode helper code that is embedded into bpfilter.ko The steps to build bpfilter.ko are the following: - main.c is compiled by HOSTCC into the bpfilter_umh elf executable file - with quite a bit of objcopy and Makefile magic the bpfilter_umh elf file is converted into bpfilter_umh.o object file with _binary_net_bpfilter_bpfilter_umh_start and _end symbols Example: $ nm ./bld_x64/net/bpfilter/bpfilter_umh.o 0000000000004cf8 T _binary_net_bpfilter_bpfilter_umh_end 0000000000004cf8 A _binary_net_bpfilter_bpfilter_umh_size 0000000000000000 T _binary_net_bpfilter_bpfilter_umh_start - bpfilter_umh.o and bpfilter_kern.o are linked together into bpfilter.ko bpfilter_kern.c is a normal kernel module code that calls the fork_usermode_blob() helper to execute part of its own data as a user mode process. Notice that _binary_net_bpfilter_bpfilter_umh_start - end is placed into .init.rodata section, so it's freed as soon as __init function of bpfilter.ko is finished. As part of __init the bpfilter.ko does first request/reply action via two unix pipe provided by fork_usermode_blob() helper to make sure that umh is healthy. If not it will kill it via pid. Later bpfilter_process_sockopt() will be called from bpfilter hooks in get/setsockopt() to pass iptable commands into umh via bpfilter.ko If admin does 'rmmod bpfilter' the __exit code bpfilter.ko will kill umh as well. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-22 02:22:30 +00:00
ifeq ($(CONFIG_BPFILTER_UMH), y)
# builtin bpfilter_umh should be compiled with -static
# since rootfs isn't mounted at the time of __init
# function is called and do_execv won't find elf interpreter
HOSTLDFLAGS += -static
endif
# a bit of elf magic to convert bpfilter_umh binary into a binary blob
# inside bpfilter_umh.o elf file referenced by
# _binary_net_bpfilter_bpfilter_umh_start symbol
# which bpfilter_kern.c passes further into umh blob loader at run-time
quiet_cmd_copy_umh = GEN $@
cmd_copy_umh = echo ':' > $(obj)/.bpfilter_umh.o.cmd; \
bpfilter: fix build error bpfilter Makefile assumes that the system locale is en_US, and the parsing of objdump output fails. Set LC_ALL=C and, while at it, rewrite the objdump parsing so it spawns only 2 processes instead of 7. Fixes: d2ba09c17a064 ("net: add skeleton of bpfilter kernel module") Signed-off-by: Matteo Croce <mcroce@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-19 15:16:20 +00:00
$(OBJCOPY) -I binary \
bpfilter: fix user mode helper cross compilation Use $(OBJDUMP) instead of literal 'objdump' to avoid using host toolchain when cross compiling. Fixes: 421780fd4983 ("bpfilter: fix build error") Signed-off-by: Matteo Croce <mcroce@redhat.com> Reported-by: Stefano Brivio <sbrivio@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-20 14:04:34 +00:00
`LC_ALL=C $(OBJDUMP) -f net/bpfilter/bpfilter_umh \
bpfilter: fix build error bpfilter Makefile assumes that the system locale is en_US, and the parsing of objdump output fails. Set LC_ALL=C and, while at it, rewrite the objdump parsing so it spawns only 2 processes instead of 7. Fixes: d2ba09c17a064 ("net: add skeleton of bpfilter kernel module") Signed-off-by: Matteo Croce <mcroce@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-19 15:16:20 +00:00
|awk -F' |,' '/file format/{print "-O",$$NF} \
/^architecture:/{print "-B",$$2}'` \
net: add skeleton of bpfilter kernel module bpfilter.ko consists of bpfilter_kern.c (normal kernel module code) and user mode helper code that is embedded into bpfilter.ko The steps to build bpfilter.ko are the following: - main.c is compiled by HOSTCC into the bpfilter_umh elf executable file - with quite a bit of objcopy and Makefile magic the bpfilter_umh elf file is converted into bpfilter_umh.o object file with _binary_net_bpfilter_bpfilter_umh_start and _end symbols Example: $ nm ./bld_x64/net/bpfilter/bpfilter_umh.o 0000000000004cf8 T _binary_net_bpfilter_bpfilter_umh_end 0000000000004cf8 A _binary_net_bpfilter_bpfilter_umh_size 0000000000000000 T _binary_net_bpfilter_bpfilter_umh_start - bpfilter_umh.o and bpfilter_kern.o are linked together into bpfilter.ko bpfilter_kern.c is a normal kernel module code that calls the fork_usermode_blob() helper to execute part of its own data as a user mode process. Notice that _binary_net_bpfilter_bpfilter_umh_start - end is placed into .init.rodata section, so it's freed as soon as __init function of bpfilter.ko is finished. As part of __init the bpfilter.ko does first request/reply action via two unix pipe provided by fork_usermode_blob() helper to make sure that umh is healthy. If not it will kill it via pid. Later bpfilter_process_sockopt() will be called from bpfilter hooks in get/setsockopt() to pass iptable commands into umh via bpfilter.ko If admin does 'rmmod bpfilter' the __exit code bpfilter.ko will kill umh as well. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-22 02:22:30 +00:00
--rename-section .data=.init.rodata $< $@
$(obj)/bpfilter_umh.o: $(obj)/bpfilter_umh
$(call cmd,copy_umh)
obj-$(CONFIG_BPFILTER_UMH) += bpfilter.o
bpfilter-objs += bpfilter_kern.o bpfilter_umh.o
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