refactor: complete applyingconst to bpf variables

bpf/generictracer/k_tracer.c

@@ -130,7 +130,7 @@ int BPF_KRETPROBE(obi_kretprobe_sys_accept4, s32 fd) {
         // TODO: try to merge with store_accept_fd_info() above
         bpf_map_update_elem(&fd_to_connection, &key, &info.p_conn.conn, BPF_ANY);
 
-        u64 accept_time = bpf_ktime_get_ns();
+        const u64 accept_time = bpf_ktime_get_ns();
 
         bpf_map_update_elem(&accepted_connections, &info.p_conn.conn, &accept_time, BPF_ANY);
     } else {
@@ -1002,7 +1002,7 @@ int obi_socket__http_filter(struct __sk_buff *skb) {
         //bpf_d_printk("http buf=[%s] [%s]", buf, __FUNCTION__);
         //d_print_http_connection_info(&conn);
         if (packet_type == PACKET_TYPE_REQUEST) {
-            u64 cookie = bpf_get_socket_cookie(skb);
+            const u64 cookie = bpf_get_socket_cookie(skb);
             //bpf_dbg_printk("cookie=%llx, len=%d, buf=[%s]", cookie, len, buf);
             //dbg_print_http_connection_info(&conn);
 
@@ -1170,8 +1170,8 @@ int obi_handle_buf_with_args(void *ctx) {
                      (info) ? still_reading(info) : 0);
 
         if (info && !info->submitted) {
-            u8 reading = still_reading(info);
-            u8 responding = still_responding(info);
+            const u8 reading = still_reading(info);
+            const u8 responding = still_responding(info);
             // Still reading checks if we are processing buffers of a HTTP request
             // that has started, but we haven't seen a response yet.
             if (reading || responding) {

bpf/gotracer/go_nethttp.c

@@ -258,7 +258,7 @@ int obi_uprobe_ginGetValueRet(struct pt_regs *ctx) {
         bpf_map_lookup_elem(&ongoing_http_server_requests, &g_key);
 
     off_table_t *ot = get_offsets_table();
-    u64 fullpath_off = go_offset_of(ot, (go_offset){.v = _gin_fullpath_pos});
+    const u64 fullpath_off = go_offset_of(ot, (go_offset){.v = _gin_fullpath_pos});
 
     bpf_dbg_printk("goroutine_addr=%lx, invocation=%llx, fullpath_off=%d",
                    goroutine_addr,
@@ -273,7 +273,7 @@ int obi_uprobe_ginGetValueRet(struct pt_regs *ctx) {
                 // registers
                 if (fullpath_off == _gin_fullpath_off_pre_17) {
                     void *ptr = GO_PARAM8(ctx);
-                    u64 len = (u64)GO_PARAM9(ctx);
+                    const u64 len = (u64)GO_PARAM9(ctx);
 
                     if (ptr) {
                         bpf_dbg_printk("pre gin 1.7.0 fullPath from: %llx", ptr);
@@ -282,7 +282,7 @@ int obi_uprobe_ginGetValueRet(struct pt_regs *ctx) {
                     }
                 } else {
                     void *ptr = GO_PARAM6(ctx);
-                    u64 len = (u64)GO_PARAM7(ctx);
+                    const u64 len = (u64)GO_PARAM7(ctx);
 
                     if (ptr) {
                         bpf_dbg_printk("post gin 1.7.0 fullPath from: %llx", ptr);
@@ -950,7 +950,7 @@ int obi_uprobe_http2ResponseWriterStateWriteHeader(struct pt_regs *ctx) {
     bpf_dbg_printk("=== uprobe/http2ResponseWriterStateWriteHeader ===");
 
     void *goroutine_addr = GOROUTINE_PTR(ctx);
-    u64 status = (u64)GO_PARAM2(ctx);
+    const u64 status = (u64)GO_PARAM2(ctx);
     bpf_dbg_printk("goroutine_addr=%lx, status=%d", goroutine_addr, status);
     go_addr_key_t g_key = {};
     go_addr_key_from_id(&g_key, goroutine_addr);

bpf/gotracer/go_redis.c

@@ -130,7 +130,7 @@ int obi_uprobe_redis_with_writer(struct pt_regs *ctx) {
                     &conn_ptr, sizeof(conn_ptr), (void *)(tcp_conn_ptr + 8)); // find conn
                 bpf_dbg_printk("conn_ptr=%llx", conn_ptr);
                 if (conn_ptr) {
-                    u8 ok = get_conn_info(conn_ptr, &req->conn);
+                    const u8 ok = get_conn_info(conn_ptr, &req->conn);
                     if (!ok) {
                         __builtin_memset(&req->conn, 0, sizeof(connection_info_t));
                     }
@@ -161,7 +161,7 @@ int obi_uprobe_redis_with_writer_ret(struct pt_regs *ctx) {
             if (bw) {
                 bpf_dbg_printk("Found bw: %llx", bw);
 
-                u64 io_writer_buf_ptr_pos =
+                const u64 io_writer_buf_ptr_pos =
                     go_offset_of(ot, (go_offset){.v = _io_writer_buf_ptr_pos});
 
                 void *buf = 0;

bpf/gotracer/go_runtime.c

@@ -159,7 +159,7 @@ enum offsets : u8 {
 
 SEC("uprobe/runtime.mstart1")
 int obi_uprobe_runtime_mstart1(struct pt_regs *ctx) {
-    u64 pid_tgid = bpf_get_current_pid_tgid();
+    const u64 pid_tgid = bpf_get_current_pid_tgid();
 
     void *g = (void *)GOROUTINE_PTR(ctx);
     void *m = NULL;
@@ -190,7 +190,7 @@ int obi_uprobe_runtime_mexit(struct pt_regs *ctx) {
 // gp *g, oldval, newval uint32
 SEC("uprobe/runtime.casgstatus")
 int obi_uprobe_runtime_casgstatus(struct pt_regs *ctx) {
-    u64 pid_tgid = bpf_get_current_pid_tgid();
+    const u64 pid_tgid = bpf_get_current_pid_tgid();
 
     void *g = (void *)GO_PARAM1(ctx);
     void *m = NULL;
@@ -219,7 +219,7 @@ int obi_uprobe_runtime_casgstatus(struct pt_regs *ctx) {
     };
     grpc_srv_func_invocation_t *invocation;
 
-    u32 newval = (u32)(uintptr_t)GO_PARAM3(ctx);
+    const u32 newval = (u32)(uintptr_t)GO_PARAM3(ctx);
     switch (newval) {
     case g_running:
     case g_syscall:

bpf/gpuevent/cuda.c

@@ -34,7 +34,7 @@ enum {
 SEC("uprobe/cudaLaunchKernel")
 int BPF_KPROBE(obi_cuda_launch, u64 func_off, u64 grid_xy, u64 grid_z, u64 block_xy, u64 block_z) {
     (void)ctx;
-    u64 id = bpf_get_current_pid_tgid();
+    const u64 id = bpf_get_current_pid_tgid();
 
     if (!valid_pid(id)) {
         return 0;
@@ -68,7 +68,7 @@ int BPF_KPROBE(obi_cuda_malloc, void **devPtr, size_t size) {
     (void)ctx;
     (void)devPtr;
 
-    u64 id = bpf_get_current_pid_tgid();
+    const u64 id = bpf_get_current_pid_tgid();
 
     if (!valid_pid(id)) {
         return 0;
@@ -96,7 +96,7 @@ int BPF_KPROBE(obi_cuda_memcpy, void *dst, void *src, size_t size, u8 kind) {
     (void)dst;
     (void)src;
 
-    u64 id = bpf_get_current_pid_tgid();
+    const u64 id = bpf_get_current_pid_tgid();
 
     if (!valid_pid(id)) {
         return 0;
@@ -122,7 +122,7 @@ int BPF_KPROBE(obi_cuda_memcpy, void *dst, void *src, size_t size, u8 kind) {
 SEC("uprobe/cudaGraphLaunch")
 int BPF_KPROBE(obi_graph_launch) {
     (void)ctx;
-    u64 id = bpf_get_current_pid_tgid();
+    const u64 id = bpf_get_current_pid_tgid();
 
     if (!valid_pid(id)) {
         return 0;

bpf/logenricher/logenricher.c

@@ -133,7 +133,7 @@ int BPF_KPROBE(obi_kprobe_tty_write, struct kiocb *iocb, struct iov_iter *from)
     struct tty_file_private *tfp =
         (struct tty_file_private *)BPF_CORE_READ(iocb, ki_filp, private_data);
     struct tty_struct *tty = BPF_CORE_READ(tfp, tty);
-    bool is_master = tty_driver_is_pty(tty) && tty_driver_is_master(tty);
+    const bool is_master = tty_driver_is_pty(tty) && tty_driver_is_master(tty);
 
     struct tty_dev master = {};
     struct tty_dev slave = {};

bpf/netolly/flows.c

@@ -165,7 +165,7 @@ static inline int flow_monitor(struct __sk_buff *skb) {
     }
     id.if_index = skb->ifindex;
 
-    u64 current_time = bpf_ktime_get_ns();
+    const u64 current_time = bpf_ktime_get_ns();
 
     // TODO: we need to add spinlock here when we deprecate versions prior to 5.1, or provide
     // a spinlocked alternative version and use it selectively https://lwn.net/Articles/779120/
@@ -181,7 +181,7 @@ static inline int flow_monitor(struct __sk_buff *skb) {
         }
         aggregate_flow->flags |= flags;
 
-        long ret = bpf_map_update_elem(&aggregated_flows, &id, aggregate_flow, BPF_ANY);
+        const long ret = bpf_map_update_elem(&aggregated_flows, &id, aggregate_flow, BPF_ANY);
         if (trace_messages && ret != 0) {
             // usually error -16 (-EBUSY) is printed here.
             // In this case, the flow is dropped, as submitting it to the ringbuffer would cause
@@ -234,7 +234,7 @@ static inline int flow_monitor(struct __sk_buff *skb) {
 
         // even if we know that the entry is new, another CPU might be concurrently inserting a flow
         // so we need to specify BPF_ANY
-        long ret = bpf_map_update_elem(&aggregated_flows, &id, &new_flow, BPF_ANY);
+        const long ret = bpf_map_update_elem(&aggregated_flows, &id, &new_flow, BPF_ANY);
         if (ret != 0) {
             // usually error -16 (-EBUSY) or -7 (E2BIG) is printed here.
             // In this case, we send the single-packet flow via ringbuffer as in the worst case we can have

bpf/netolly/flows_common.h

@@ -131,7 +131,7 @@ static inline u8 get_connection_initiator(flow_id *id, u16 flags) {
     conn_initiator_key initiator_key;
     // from the initiator_key with sorted ip/ports, know the index of the
     // endpoint that that initiated the connection, which might be the low or the high address
-    u8 low_is_src = fill_conn_initiator_key(id, &initiator_key);
+    const u8 low_is_src = fill_conn_initiator_key(id, &initiator_key);
     u8 *initiator = (u8 *)bpf_map_lookup_elem(&conn_initiators, &initiator_key);
     u8 initiator_index = INITIATOR_UNKNOWN;
     if (initiator == NULL) {

bpf/netolly/flows_sock.c

@@ -203,7 +203,7 @@ int obi_socket__filter(struct __sk_buff *skb) {
         return TC_ACT_UNSPEC;
     }
 
-    u64 current_time = bpf_ktime_get_ns();
+    const u64 current_time = bpf_ktime_get_ns();
 
     // TODO: we need to add spinlock here when we deprecate versions prior to 5.1, or provide
     // a spinlocked alternative version and use it selectively https://lwn.net/Articles/779120/
@@ -219,7 +219,7 @@ int obi_socket__filter(struct __sk_buff *skb) {
         }
         aggregate_flow->flags |= flags;
 
-        long ret = bpf_map_update_elem(&aggregated_flows, &id, aggregate_flow, BPF_ANY);
+        const long ret = bpf_map_update_elem(&aggregated_flows, &id, aggregate_flow, BPF_ANY);
         if (trace_messages && ret != 0) {
             // usually error -16 (-EBUSY) is printed here.
             // In this case, the flow is dropped, as submitting it to the ringbuffer would cause
@@ -271,7 +271,7 @@ int obi_socket__filter(struct __sk_buff *skb) {
 
         // even if we know that the entry is new, another CPU might be concurrently inserting a flow
         // so we need to specify BPF_ANY
-        long ret = bpf_map_update_elem(&aggregated_flows, &id, &new_flow, BPF_ANY);
+        const long ret = bpf_map_update_elem(&aggregated_flows, &id, &new_flow, BPF_ANY);
         if (ret != 0) {
             // usually error -16 (-EBUSY) or -7 (E2BIG) is printed here.
             // In this case, we send the single-packet flow via ringbuffer as in the worst case we can have

bpf/pid/pid.h

@@ -22,12 +22,12 @@ enum { k_prime_hash = 192053 }; // closest prime to k_max_concurrent_pids * 64
 
 static __always_inline u8 pid_matches(pid_data_t *p) {
     // combine the namespace id and the pid into one single u64
-    u64 k = (((u64)p->ns) << 32) | p->pid;
+    const u64 k = (((u64)p->ns) << 32) | p->pid;
 
     // divide with prime number lower than max pids * 64, modulo with primes gives good hash functions
-    u32 h = (u32)(k % k_prime_hash);
-    u32 segment = h / 64; // divide by the segment size (8 bytes) to find the segment
-    u32 bit = h & 63;     // lowest 64 bits gives us the placement inside the segment
+    const u32 h = (u32)(k % k_prime_hash);
+    const u32 segment = h / 64; // divide by the segment size (8 bytes) to find the segment
+    const u32 bit = h & 63;     // lowest 64 bits gives us the placement inside the segment
 
     u64 *v = bpf_map_lookup_elem(&valid_pids, &segment);
     if (!v) {
@@ -40,7 +40,7 @@ static __always_inline u8 pid_matches(pid_data_t *p) {
 }
 
 static __always_inline u32 valid_pid(u64 id) {
-    u32 a_pid = id >> 32;
+    const u32 a_pid = id >> 32;
     // accept all PIDs if debugging OTEL_EBPF_BPF_PID_FILTER_OFF option is set
     if (!filter_pids) {
         return a_pid;
@@ -63,15 +63,15 @@ static __always_inline u32 valid_pid(u64 id) {
     if (a_pid != 0) {
         pid_data_t p_key = {.pid = a_pid, .ns = pid_ns_id};
 
-        u8 found_ns_pid = pid_matches(&p_key);
+        const u8 found_ns_pid = pid_matches(&p_key);
 
         if (found_ns_pid) {
             bpf_map_update_elem(&pid_cache, &a_pid, &a_pid, BPF_ANY);
             return a_pid;
         } else if (ns_ppid != 0) {
             pid_data_t pp_key = {.pid = ns_ppid, .ns = pid_ns_id};
 
-            u8 found_ns_ppid = pid_matches(&pp_key);
+            const u8 found_ns_ppid = pid_matches(&pp_key);
 
             if (found_ns_ppid) {
                 bpf_map_update_elem(&pid_cache, &a_pid, &a_pid, BPF_ANY);

bpf/watcher/watcher.c

@@ -37,7 +37,7 @@ int obi_kprobe_sys_bind(struct pt_regs *ctx) {
         return 0;
     }
 
-    u16 port = get_sockaddr_port_user(addr);
+    const u16 port = get_sockaddr_port_user(addr);
 
     if (!port) {
         return 0;