![]() An in-kernel verifier statically determines that theĮBPF program terminates and is safe to execute. Thus, whether a specific programĬontinues to live inside the kernel depends on how it is further attached toĪ given kernel subsystem after it was loaded via bpf().Įach eBPF program is a set of instructions that is safe to run Has been closed by the user-space program. Subsystem holds a reference to the eBPF program after the file descriptor Tc-bpf(8), the program will continue to stay alive inside the kernelĮven after the process that loaded the program exits. ![]() Generally, eBPF programs are loaded by the user process andĪutomatically unloaded when the process exits. SeeīPF_MAP_TYPE_PROG_ARRAY below for further details. Lookup fails, the current program continues its execution. Have been previously loaded into the kernel via bpf(). All programs referred to in a program-array map must The map can be modified, so program functionality can be altered based on ![]() At run time, the program file descriptors stored in The level of nesting has a fixed limit of 32, so that infinite In the map is performed, the program flow is redirected in-place to theīeginning of another eBPF program and does not return back to the calling Map stores file descriptors referring to other eBPF programs. There's one special map type, called a program array. Process and eBPF program to decide what they store inside maps. DifferentĮBPF programs can access the same maps in parallel. In other words, a key/value for a given map can have an arbitraryĪ user process can create multiple maps (with key/value-pairsīeing opaque bytes of data) and access them via file descriptors. Specifies the size of the key and the size of the value at map-creation Data types are generally treated as binary blobs, so a user just For both cBPF and eBPF programs, the kernel staticallyĪnalyzes the programs before loading them, in order to ensure that theyĮBPF extends cBPF in multiple ways, including the ability to callĪ fixed set of in-kernel helper functions (via the BPF_CALL opcodeĮxtension provided by eBPF) and access shared data structures such as eBPFĮBPF maps are a generic data structure for storage of differentĭata types. Similar to the original ("classic") BPF (cBPF) used to filter Related to extended Berkeley Packet Filters. The bpf() system call performs a range of operations Bpf - perform a command on an extended BPF map or program SYNOPSIS ¶ #include int bpf(int cmd, union bpf_attr * attr, unsigned int size ) DESCRIPTION ¶ ![]()
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