From man 2 bpf:
The eBPF program type (prog_type) determines the subset of kernel helper functions that the program may call. The program type also determines the program input (context)—the format of struct bpf_context (which is the data blob passed into the eBPF program as the first argument).
For example, a tracing program does not have the exact same subset of helper functions as a socket filter program (though they may have some helpers in common). Similarly, the input (context) for a tracing program is a set of register values, while for a socket filter it is a network packet.
The set of functions available to eBPF programs of a given type may increase in the future
BPF_PROG_TYPE_SOCKET_FILTER
BPF_PROG_TYPE_KPROBE
BPF_PROG_TYPE_SCHED_CLS
BPF_PROG_TYPE_SCHED_ACT
BPF_PROG_TYPE_TRACEPOINT
BPF_PROG_TYPE_XDP
BPF_PROG_TYPE_PERF_EVENT
BPF_PROG_TYPE_CGROUP_SKB
BPF_PROG_TYPE_CGROUP_SOCK
BPF_PROG_TYPE_LWT_IN
BPF_PROG_TYPE_LWT_OUT
BPF_PROG_TYPE_LWT_XMIT
BPF_PROG_TYPE_SOCK_OPS
BPF_PROG_TYPE_SK_SKB
BPF_PROG_TYPE_CGROUP_DEVICE
BPF_PROG_TYPE_SK_MSG
BPF_PROG_TYPE_RAW_TRACEPOINT
BPF_PROG_TYPE_CGROUP_SOCK_ADDR
BPF_PROG_TYPE_LWT_SEG6LOCAL
BPF_PROG_TYPE_LIRC_MODE2
BPF_PROG_TYPE_SK_REUSEPORT
BPF_PROG_TYPE_FLOW_DISSECTOR
/* See /usr/include/linux/bpf.h for the full list. */