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yunwei37yunwei37
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add basic of xdp lb and xdp firewall
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‎src/41-xdp-loadbalancer/.gitignore‎

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.output
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uprobe
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merge-btf
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*.btf
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xdp_lb

‎src/41-xdp-loadbalancer/Makefile‎

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# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
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OUTPUT := .output
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CLANG ?= clang
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LIBBPF_SRC := $(abspath ../third_party/libbpf/src)
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BPFTOOL_SRC := $(abspath ../third_party/bpftool/src)
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LIBBPF_OBJ := $(abspath $(OUTPUT)/libbpf.a)
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BPFTOOL_OUTPUT ?= $(abspath $(OUTPUT)/bpftool)
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BPFTOOL ?= $(BPFTOOL_OUTPUT)/bootstrap/bpftool
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LIBBLAZESYM_SRC := $(abspath ../third_party/blazesym/)
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LIBBLAZESYM_OBJ := $(abspath $(OUTPUT)/libblazesym.a)
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LIBBLAZESYM_HEADER := $(abspath $(OUTPUT)/blazesym.h)
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ARCH ?= $(shell uname -m | sed 's/x86_64/x86/' \
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| sed 's/arm.*/arm/' \
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| sed 's/aarch64/arm64/' \
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| sed 's/ppc64le/powerpc/' \
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| sed 's/mips.*/mips/' \
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| sed 's/riscv64/riscv/' \
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| sed 's/loongarch64/loongarch/')
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VMLINUX := ../third_party/vmlinux/$(ARCH)/vmlinux.h
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# Use our own libbpf API headers and Linux UAPI headers distributed with
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# libbpf to avoid dependency on system-wide headers, which could be missing or
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# outdated
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INCLUDES := -I$(OUTPUT) -I../third_party/libbpf/include/uapi -I$(dir $(VMLINUX))
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CFLAGS := -g -Wall
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ALL_LDFLAGS := $(LDFLAGS) $(EXTRA_LDFLAGS)
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APPS = xdp_lb
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CARGO ?= $(shell which cargo)
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ifeq ($(strip $(CARGO)),)
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BZS_APPS :=
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else
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BZS_APPS :=
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APPS += $(BZS_APPS)
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# Required by libblazesym
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ALL_LDFLAGS += -lrt -ldl -lpthread -lm
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endif
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# Get Clang's default includes on this system. We'll explicitly add these dirs
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# to the includes list when compiling with `-target bpf` because otherwise some
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# architecture-specific dirs will be "missing" on some architectures/distros -
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# headers such as asm/types.h, asm/byteorder.h, asm/socket.h, asm/sockios.h,
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# sys/cdefs.h etc. might be missing.
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#
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# Use '-idirafter': Don't interfere with include mechanics except where the
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# build would have failed anyways.
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CLANG_BPF_SYS_INCLUDES ?= $(shell $(CLANG) -v -E - </dev/null 2>&1 \
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| sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }')
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ifeq ($(V),1)
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Q =
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msg =
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else
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Q = @
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msg = @printf ' %-8s %s%s\n' \
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"$(1)" \
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"$(patsubst $(abspath $(OUTPUT))/%,%,$(2))" \
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"$(if $(3), $(3))";
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MAKEFLAGS += --no-print-directory
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endif
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define allow-override
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$(if $(or $(findstring environment,$(origin $(1))),\
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$(findstring command line,$(origin $(1)))),,\
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$(eval $(1) = $(2)))
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endef
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$(call allow-override,CC,$(CROSS_COMPILE)cc)
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$(call allow-override,LD,$(CROSS_COMPILE)ld)
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.PHONY: all
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all: $(APPS)
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.PHONY: clean
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clean:
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$(call msg,CLEAN)
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$(Q)rm -rf $(OUTPUT) $(APPS)
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$(OUTPUT) $(OUTPUT)/libbpf $(BPFTOOL_OUTPUT):
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$(call msg,MKDIR,$@)
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$(Q)mkdir -p $@
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# Build libbpf
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$(LIBBPF_OBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)/libbpf
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$(call msg,LIB,$@)
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$(Q)$(MAKE) -C $(LIBBPF_SRC) BUILD_STATIC_ONLY=1 \
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OBJDIR=$(dir $@)/libbpf DESTDIR=$(dir $@) \
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INCLUDEDIR= LIBDIR= UAPIDIR= \
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install
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# Build bpftool
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$(BPFTOOL): | $(BPFTOOL_OUTPUT)
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$(call msg,BPFTOOL,$@)
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$(Q)$(MAKE) ARCH= CROSS_COMPILE= OUTPUT=$(BPFTOOL_OUTPUT)/ -C $(BPFTOOL_SRC) bootstrap
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$(LIBBLAZESYM_SRC)/target/release/libblazesym.a::
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$(Q)cd $(LIBBLAZESYM_SRC) && $(CARGO) build --features=cheader,dont-generate-test-files --release
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$(LIBBLAZESYM_OBJ): $(LIBBLAZESYM_SRC)/target/release/libblazesym.a | $(OUTPUT)
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$(call msg,LIB, $@)
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$(Q)cp $(LIBBLAZESYM_SRC)/target/release/libblazesym.a $@
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$(LIBBLAZESYM_HEADER): $(LIBBLAZESYM_SRC)/target/release/libblazesym.a | $(OUTPUT)
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$(call msg,LIB,$@)
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$(Q)cp $(LIBBLAZESYM_SRC)/target/release/blazesym.h $@
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# Build BPF code
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$(OUTPUT)/%.bpf.o: %.bpf.c $(LIBBPF_OBJ) $(wildcard %.h) $(VMLINUX) | $(OUTPUT) $(BPFTOOL)
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$(call msg,BPF,$@)
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$(Q)$(CLANG) -g -O2 -target bpf -D__TARGET_ARCH_$(ARCH) \
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$(INCLUDES) $(CLANG_BPF_SYS_INCLUDES) \
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-c $(filter %.c,$^) -o $(patsubst %.bpf.o,%.tmp.bpf.o,$@)
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$(Q)$(BPFTOOL) gen object $@ $(patsubst %.bpf.o,%.tmp.bpf.o,$@)
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# Generate BPF skeletons
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$(OUTPUT)/%.skel.h: $(OUTPUT)/%.bpf.o | $(OUTPUT) $(BPFTOOL)
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$(call msg,GEN-SKEL,$@)
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$(Q)$(BPFTOOL) gen skeleton $< > $@
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# Build user-space code
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$(patsubst %,$(OUTPUT)/%.o,$(APPS)): %.o: %.skel.h
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$(OUTPUT)/%.o: %.c $(wildcard %.h) | $(OUTPUT)
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$(call msg,CC,$@)
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$(Q)$(CC) $(CFLAGS) $(INCLUDES) -c $(filter %.c,$^) -o $@
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$(patsubst %,$(OUTPUT)/%.o,$(BZS_APPS)): $(LIBBLAZESYM_HEADER)
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$(BZS_APPS): $(LIBBLAZESYM_OBJ)
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# Build application binary
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$(APPS): %: $(OUTPUT)/%.o $(LIBBPF_OBJ) | $(OUTPUT)
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$(call msg,BINARY,$@)
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$(Q)$(CC) $(CFLAGS) $^ $(ALL_LDFLAGS) -lelf -lz -o $@
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# delete failed targets
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.DELETE_ON_ERROR:
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# keep intermediate (.skel.h, .bpf.o, etc) targets
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.SECONDARY:

‎src/41-xdp-loadbalancer/README.md‎

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‎src/41-xdp-loadbalancer/xdp_lb.bpf.c‎

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// xdp_lb.bpf.c
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include <linux/if_ether.h>
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#include <linux/ip.h>
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#include <linux/in.h>
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 2); // Two backends
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__type(key, __u32);
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__type(value, __u32); // Backend IPs
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} backends SEC(".maps");
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SEC("xdp")
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int xdp_load_balancer(struct xdp_md *ctx) {
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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struct ethhdr *eth = data;
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if ((void *)(eth + 1) > data_end)
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return XDP_PASS;
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if (eth->h_proto != __constant_htons(ETH_P_IP))
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return XDP_PASS;
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struct iphdr *iph = (struct iphdr *)(eth + 1);
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if ((void *)(iph + 1) > data_end)
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return XDP_PASS;
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if (iph->protocol != IPPROTO_TCP && iph->protocol != IPPROTO_UDP)
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return XDP_PASS;
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__u32 key = 0;
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static __u32 cnt = 0;
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__u32 *backend_ip = bpf_map_lookup_elem(&backends, &key);
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if (!backend_ip)
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return XDP_PASS;
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cnt = (cnt + 1) % 2; // Round-robin
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key = cnt;
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backend_ip = bpf_map_lookup_elem(&backends, &key);
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if (backend_ip) {
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iph->daddr = *backend_ip; // Redirect to the backend IP
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iph->check = 0; // Needs recomputation in real cases
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}
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return XDP_TX; // Transmit modified packet back
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}
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char _license[] SEC("license") = "GPL";

‎src/41-xdp-loadbalancer/xdp_lb.c‎

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// xdp_lb.c
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#include <stdio.h>
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#include <stdlib.h>
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#include <bpf/libbpf.h>
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#include <bpf/bpf.h>
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#include <net/if.h>
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#include <linux/if_link.h>
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#include "xdp_lb.skel.h" // This header is auto-generated by bpftool
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#define IFACE "eth0" // Replace with your network interface
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static int set_up_backends(struct xdp_lb_bpf *skel) {
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__u32 backend1 = htonl(0xC0A80102); // 192.168.1.2
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__u32 backend2 = htonl(0xC0A80103); // 192.168.1.3
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__u32 key = 0;
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if (bpf_map_update_elem(bpf_map__fd(skel->maps.backends), &key, &backend1, BPF_ANY) < 0) {
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fprintf(stderr, "Failed to update backend 1\n");
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return -1;
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}
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key = 1;
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if (bpf_map_update_elem(bpf_map__fd(skel->maps.backends), &key, &backend2, BPF_ANY) < 0) {
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fprintf(stderr, "Failed to update backend 2\n");
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return -1;
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}
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return 0;
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}
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int main() {
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struct xdp_lb_bpf *skel;
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int err, ifindex;
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// Load and verify the eBPF skeleton
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skel = xdp_lb_bpf__open();
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if (!skel) {
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fprintf(stderr, "Failed to open and load skeleton\n");
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return 1;
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}
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// Load eBPF program
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err = xdp_lb_bpf__load(skel);
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if (err) {
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fprintf(stderr, "Failed to load BPF program: %d\n", err);
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return 1;
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}
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// Set up the backend IP addresses
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if (set_up_backends(skel) < 0) {
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fprintf(stderr, "Failed to set up backend IP addresses\n");
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return 1;
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}
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// Get interface index
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ifindex = if_nametoindex(IFACE);
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if (ifindex == 0) {
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perror("if_nametoindex");
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return 1;
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}
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// Attach the XDP program
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err = bpf_xdp_attach(ifindex, bpf_program__fd(skel->progs.xdp_load_balancer), XDP_FLAGS_SKB_MODE, NULL);
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if (err) {
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fprintf(stderr, "Failed to attach XDP program: %d\n", err);
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return 1;
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}
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printf("XDP Load Balancer is running on interface %s...\n", IFACE);
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sleep(60); // Keep running for 60 seconds
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// Detach the XDP program before exiting
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err = bpf_xdp_detach(ifindex, XDP_FLAGS_SKB_MODE, NULL);
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if (err) {
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fprintf(stderr, "Failed to detach XDP program: %d\n", err);
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return 1;
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}
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// Clean up
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xdp_lb_bpf__destroy(skel);
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return 0;
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}

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