Removing trailing white spaces and fixing typo (#5383)

* Remove trailing white spaces
Trailing whitespaces are removed from all files, empty lines and
image files are preserved. This patch is created using the following
shell commands:

  find . -type f -not -path '*/\.*' -exec sed -i '/^$/!s/[ \t]*$//' {} \;

* docs/reference_guide.md: Fix typo

Author: Bojun-Seo

FAQ.txt

@@ -29,7 +29,7 @@ A: The so-called Kernel lockdown might be the root cause. Try disabling it with
        echo 1 > /proc/sys/kernel/sysrq
        echo x > /proc/sysrq-trigger
    Also see https://github.com/iovisor/bcc/issues/2525
-   
+
    If you have Secure Boot enabled you need to press Alt-PrintScr-x on the keyboard instead:
    ```
    This sysrq operation is disabled from userspace.

INSTALL.md

@@ -311,7 +311,7 @@ mv /lib/modules/$KERNEL_VERSION-microsoft-standard-WSL2+/ /lib/modules/$KERNEL_V
 
 Then you can install bcc tools package according your distribution.
 
-If you met some problems, try to 
+If you met some problems, try to
 ```
 sudo mount -t debugfs debugfs /sys/kernel/debug
 ```
@@ -387,7 +387,7 @@ sudo apt install -y zip bison build-essential cmake flex git libedit-dev \
 sudo apt install -y zip bison build-essential cmake flex git libedit-dev \
   libllvm14 llvm-14-dev libclang-14-dev python3 zlib1g-dev libelf-dev libfl-dev python3-setuptools \
   liblzma-dev libdebuginfod-dev arping netperf iperf
-  
+
 # For Lunar Lobster (23.04)
 sudo apt install -y zip bison build-essential cmake flex git libedit-dev \
   libllvm15 llvm-15-dev libclang-15-dev python3 zlib1g-dev libelf-dev libfl-dev python3-setuptools \
@@ -433,7 +433,7 @@ suppose you're running with root or add sudo first
 ### Install build dependencies
 ```
 dnf install -y bison cmake ethtool flex git iperf3 libstdc++-devel python3-netaddr python3-pip gcc gcc-c++ make zlib-devel elfutils-libelf-devel
-# dnf install -y luajit luajit-devel ## if use luajit, will report some lua function(which in lua5.3) undefined problem 
+# dnf install -y luajit luajit-devel ## if use luajit, will report some lua function(which in lua5.3) undefined problem
 dnf install -y clang clang-devel llvm llvm-devel llvm-static ncurses-devel
 dnf -y install netperf
 pip3 install pyroute2
@@ -449,7 +449,7 @@ cd bcc-build/
 ## here llvm should always link shared library
 cmake ../bcc -DCMAKE_INSTALL_PREFIX=/usr -DENABLE_LLVM_SHARED=1
 make -j10
-make install 
+make install
 
 ```
 after install, you may add bcc directory to your $PATH, which you can add to ~/.bashrc
@@ -460,20 +460,20 @@ export PATH=$bcctools:$bccexamples:$PATH
 ```
 ### let path take effect
 ```
-source ~/.bashrc 
+source ~/.bashrc
 ```
-then run 
+then run
 ```
 hello_world.py
 ```
-Or 
+Or
 ```
 cd /usr/share/bcc/examples
 ./hello_world.py
 ./tracing/bitehist.py
 
 cd /usr/share/bcc/tools
-./bitesize 
+./bitesize
 
 ```
 

docker/build/Dockerfile.ubuntu

@@ -77,7 +77,7 @@ do \
       then \
         apt-get install -y libpolly-${version}-dev; \
       fi; \
-done \ 
+done \
 && \
       apt-get -y clean'
 

docs/reference_guide.md

@@ -2616,7 +2616,7 @@ cannot call GPL only function from proprietary program
 
 eBPF program compilation needs kernel sources or kernel headers with headers
 compiled. In case your kernel sources are at a non-standard location where BCC
-cannot find then, its possible to provide BCC the absolute path of the location
+cannot find then, it's possible to provide BCC the absolute path of the location
 by setting `BCC_KERNEL_SOURCE` to it.
 
 ## 2. Kernel version overriding

docs/tutorial_bcc_python_developer.md

@@ -229,10 +229,10 @@ if BPF.get_kprobe_functions(b'blk_start_request'):
 b.attach_kprobe(event="blk_mq_start_request", fn_name="trace_start")
 
 if BPF.get_kprobe_functions(b'__blk_account_io_done'):
-    # __blk_account_io_done is available before kernel v6.4. 
+    # __blk_account_io_done is available before kernel v6.4.
     b.attach_kprobe(event="__blk_account_io_done", fn_name="trace_completion")
 elif BPF.get_kprobe_functions(b'blk_account_io_done'):
-    # blk_account_io_done is traceable (not inline) before v5.16. 
+    # blk_account_io_done is traceable (not inline) before v5.16.
     b.attach_kprobe(event="blk_account_io_done", fn_name="trace_completion")
 else:
     b.attach_kprobe(event="blk_mq_end_request", fn_name="trace_completion")
@@ -531,7 +531,7 @@ print("%-14s %-12s %-6s %s" % ("TIME(s)", "COMMAND", "PID", "UID"))
 
 def print_event(cpu, data, size):
     event = b["events"].event(data)
-    printb(b"%-14.3f %-12s %-6d %d" % ((event.ts/1000000000), 
+    printb(b"%-14.3f %-12s %-6d %d" % ((event.ts/1000000000),
            event.comm, event.pid, event.uid))
 
 # loop with callback to print_event
@@ -553,8 +553,8 @@ list``` for a list of tracepoints. Linux >= 4.7 is required to attach BPF
 programs to tracepoints.
 1. ```args->uid```: ```args``` is auto-populated to be a structure of the
 tracepoint arguments. The comment above says where you can see that structure.
-Eg:  
-    
+Eg:
+
     ```
     # sudo cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_setuid/format
     name: sys_enter_setuid
@@ -564,10 +564,10 @@ Eg:
         	field:unsigned char common_flags;       offset:2;       size:1; signed:0;
         	field:unsigned char common_preempt_count;       offset:3;       size:1; signed:0;
         	field:int common_pid;   offset:4;       size:4; signed:1;
-    
+
         	field:int __syscall_nr; offset:8;       size:4; signed:1;
         	field:uid_t uid;        offset:16;      size:8; signed:0;
-    
+
     print fmt: "uid: 0x%08lx", ((unsigned long)(REC->uid))
     ```
     In this case, there are only one member `uid` to be printed.

examples/networking/http_filter/README.md

@@ -7,7 +7,7 @@ eBPF application that parses HTTP packets and extracts (and prints on screen) th
 ## Usage Example
 
 
-    $ sudo python http-parse-complete.py 
+    $ sudo python http-parse-complete.py
     GET /pipermail/iovisor-dev/ HTTP/1.1
     HTTP/1.1 200 OK
     GET /favicon.ico HTTP/1.1
@@ -42,6 +42,6 @@ Two versions of this code are available in this repository:
 ## How to execute this sample
 
 This sample can be executed by typing either one the two commands below:
- 
+
     $ sudo python http-parse-simple.py
     $ sudo python http-parse-complete.py

examples/networking/net_monitor.py

@@ -2,8 +2,8 @@
 #
 # net_monitor.py Aggregates incoming network traffic
 # outputs source ip, destination ip, the number of their network traffic, and current time
-# how to use : net_monitor.py <net_interface> 
-# 
+# how to use : net_monitor.py <net_interface>
+#
 # Copyright (c) 2020 YoungEun Choe
 
 from bcc import BPF
@@ -34,36 +34,36 @@ def help():
 #define ETH_HLEN 14
 
 BPF_PERF_OUTPUT(skb_events);
-BPF_HASH(packet_cnt, u64, long, 256); 
+BPF_HASH(packet_cnt, u64, long, 256);
 
 int packet_monitor(struct __sk_buff *skb) {
     u8 *cursor = 0;
     u32 saddr, daddr;
     long* count = 0;
     long one = 1;
     u64 pass_value = 0;
-    
+
     struct ethernet_t *ethernet = cursor_advance(cursor, sizeof(*ethernet));
     struct ip_t *ip = cursor_advance(cursor, sizeof(*ip));
     if (ip->ver != 4)
         return 0;
-    if (ip->nextp != IP_TCP) 
+    if (ip->nextp != IP_TCP)
     {
-        if (ip -> nextp != IP_UDP) 
+        if (ip -> nextp != IP_UDP)
         {
-            if (ip -> nextp != IP_ICMP) 
-                return 0; 
+            if (ip -> nextp != IP_ICMP)
+                return 0;
         }
     }
-    
+
     saddr = ip -> src;
     daddr = ip -> dst;
 
     pass_value = saddr;
     pass_value = pass_value << 32;
     pass_value = pass_value + daddr;
 
-    count = packet_cnt.lookup(&pass_value); 
+    count = packet_cnt.lookup(&pass_value);
     if (count)  // check if this map exists
         *count += 1;
     else        // if the map for the key doesn't exist, create one
@@ -113,7 +113,7 @@ def decimal_to_human(input_value):
         formatted_time = current_time.strftime("%Y-%m-%d %H:%M:%S")
         if output_len != 0:
             print('\ncurrent packet nums:')
-        
+
         for i in range(0,output_len):
             srcdst = packet_cnt_output[i][0].value
             src = (srcdst >> 32) & 0xFFFFFFFF
@@ -124,8 +124,8 @@ def decimal_to_human(input_value):
             decimal_to_human(str(dst)) + ' ' + str(pkt_num) + ' ' + 'time : ' + formatted_time
             print(monitor_result)
 
-        packet_cnt.clear() # delete map entries after printing output. confirmed it deletes values and keys too 
-        
+        packet_cnt.clear() # delete map entries after printing output. confirmed it deletes values and keys too
+
 except KeyboardInterrupt:
     sys.stdout.close()
     pass

examples/networking/tcp_mon_block/README.md

@@ -1,24 +1,24 @@
 # eBPF tcp_mon_block
 
-This eBPF program uses netlink TC, kernel tracepoints and kprobes to monitor outgoing connections from given PIDs (usually HTTP web servers) and block connections to all addresses initiated from them, unless they are listed in allow_list.json 
+This eBPF program uses netlink TC, kernel tracepoints and kprobes to monitor outgoing connections from given PIDs (usually HTTP web servers) and block connections to all addresses initiated from them, unless they are listed in allow_list.json
 
 To run the example:
 
     1. Run python3 web_server.py . Note the server's PID (will be printed to stdout)
     2. Add the server's PID to allow_list.json . You can replace the first entry on the JSON file and put your PID instead
     3. Run tcp_mon_block.py -i network_interface_name (-v for verbose output). For example: python3 tcp_mon_block.py -i eth0
-    4. Put your web_server's listening IP in 'server_address' variable in http_client.py and run python3 http_client.py 
+    4. Put your web_server's listening IP in 'server_address' variable in http_client.py and run python3 http_client.py
 
 **Explanation**:
 
 web_server.py is a simple HTTP web server built with flask. It has a SSRF vulnerability in the route to /public_ip  (you can read more about this vulnerability here https://portswigger.net/web-security/ssrf).
 
-This route demonstrates a web server which connects to some remote API server (which is pretty common behavior) and receives some data. The attached POC simply connects to https://api.ipify.org and fetches the server's public IP, then sends it back to the client.  
-However, this specific route receives the API address to connect to from the user (http_client.py is used as the client in this POC, but in real life scenarios it will probably be a web browser). 
+This route demonstrates a web server which connects to some remote API server (which is pretty common behavior) and receives some data. The attached POC simply connects to https://api.ipify.org and fetches the server's public IP, then sends it back to the client.
+However, this specific route receives the API address to connect to from the user (http_client.py is used as the client in this POC, but in real life scenarios it will probably be a web browser).
 
 This creates a SSRF vulnerability as an attacker can put any address he/she wishes to force the web server to connect to it instead of the intended API address (https://api.ipify.org)
 
-**Run the POC twice:** 
+**Run the POC twice:**
 
 **First**, run only web_server.py and http_client.py . http_client.py will send 2 requests to the web server:
 
@@ -28,7 +28,7 @@ This creates a SSRF vulnerability as an attacker can put any address he/she wish
 
 **Now run the POC again**
 
-First run web_server.py but this time add the web server's PID to allow_list.json and then run tcp_mon_block.py as mentioned earlier. 
+First run web_server.py but this time add the web server's PID to allow_list.json and then run tcp_mon_block.py as mentioned earlier.
 
 This will make sure the web server will only connect to the predefined allow_list of addresses (this can be either an IPv4, URL or domain name), essentially blocking any connection to any address not listed in the allow_list.
 
@@ -49,7 +49,7 @@ After web_server.py initiated a connection to a non-allowed address:
 
 
 
-**Prerequisites**: 
+**Prerequisites**:
 
     1. BCC and pyroute2 for tcp_mon_block
     2. Python3 flask and requests in order to run the web_server.py and http_client.py POC

examples/networking/tunnel_monitor/README.md

@@ -27,7 +27,7 @@ dependencies. You will need nodejs+npm installed on the system to run this, but
 the setup script will only install packages in the local directory.
 
 ```
-[user@localhost tunnel_monitor]$ ./setup.sh 
+[user@localhost tunnel_monitor]$ ./setup.sh
 Cloning into 'chord-transitions'...
 remote: Counting objects: 294, done.
 ...
@@ -40,7 +40,7 @@ fastclick#1.0.6 bower_components/fastclick
 Then, start the simulation by running main.py:
 
 ```
-[root@bcc-dev tunnel_monitor]# python main.py 
+[root@bcc-dev tunnel_monitor]# python main.py
 Launching host 1 of 9
 Launching host 2 of 9
 ...

examples/networking/vlan_filter/data-plane-tracing.c

@@ -5,9 +5,9 @@
 #define IP_TCP 	6
 #define IP_UDP 17
 #define IP_ICMP 1
-/* 
+/*
   In 802.3, both the source and destination addresses are 48 bits (4 bytes) MAC address.
-  6 bytes (src) + 6 bytes (dst) + 2 bytes (type) = 14 bytes 
+  6 bytes (src) + 6 bytes (dst) + 2 bytes (type) = 14 bytes
 */
 #define ETH_HLEN 14
 
@@ -18,18 +18,18 @@
   return  0 -> DROP the packet
   return -1 -> KEEP the packet and return it to user space (userspace can read it from the socket_fd )
 */
-int vlan_filter(struct __sk_buff *skb) { 
-	u8 *cursor = 0;	
+int vlan_filter(struct __sk_buff *skb) {
+	u8 *cursor = 0;
 
 	struct ethernet_t *ethernet = cursor_advance(cursor, sizeof(*ethernet));
-	
+
 	//filter IP packets (ethernet type = 0x0800) 0x0800 is IPv4 packet
 	switch(ethernet->type){
 		case 0x0800: goto IP;
 	    	default: goto DROP;
 	}
 
-	
+
 	IP: ;
 		struct ip_t *ip = cursor_advance(cursor, sizeof(*ip));  // IP header (datagram)
 	        switch (ip->nextp){