Features of eBPF#

• Dynamic Behavior at Runtime eBPF lets you safely run custom programs inside the Linux kernel without modifying kernel code.
• Safe and Efficient Programs are verified for safety and compiled with a JIT compiler, running almost as fast as native code.
• Versatile Use Cases From networking to security and observability, eBPF unlocks deep kernel-level insights and control.

Real-world Examples#

• High-performance networking and load balancing
• Security observability with minimal overhead
• Application and container runtime enforcement
• Performance tracing and profiling

Overview#

1. A user-space process calls execve() to launch another program.
2. This triggers a syscall into the Linux kernel.
3. eBPF program attaches a custom program at this hook point to capture data.

int syscall__ret_execve(struct pt_regs *ctx)

struct comm_event event = {
  .pid = bpf_get_current_pid_tgid() >> 32,
  .type = TYPE_RETURN,
};

bpf_get_current_comm(&event.comm, sizeof(event.comm));

comm_events.perf_submit(ctx, &event, sizeof(event));

Process (User-space)#

• A user-space process calls a function bpf(), which loads eBPF bytecode into the kernel via a system call.

Linux Kernel#

• eBPF Verifier The kernel’s eBPF verifier analyzes the bytecode to ensure safety, checking for invalid memory access, infinite loops, etc. If approved, the program proceeds.
• x86_64 eBPF Program The diagram indicates the program is compiled for the x86_64 architecture.
• eBPF JIT Compiler The Just-In-Time compiler translates the verified eBPF bytecode into native machine code for efficient execution on the target architecture.

Process (Runtime Interaction)#

• A seperate process performs network operations using sendmsg() and recvmsg() system calls, which interact with the kernel’s socket layer.
• An eBPF program is attached to these system calls, allowing it to monitor or modify the network traffic.