Testing the msgb API
Buffer: 
put(4) -> data+0
Buffer: [L1]> 00 00 00 00 
put(4) -> data+4
Buffer: [L1]> 00 00 00 00 [L2]> 00 00 00 00 
put(4) -> data+8
Buffer: [L1]> 00 00 00 00 [L2]> 00 00 00 00 [L3]> 00 00 00 00 
put(4) -> data+12
Buffer: [L1]> 00 00 00 00 [L2]> 00 00 00 00 [L3]> 00 00 00 00 [L4]> 00 00 00 00 
push(4) -> data+0
Buffer: 00 00 00 00 [L1]> 00 00 00 00 [L2]> 00 00 00 00 [L3]> 00 00 00 00 [L4]> 00 00 00 00 
trim(16) -> 0
Buffer: 00 00 00 00 [L1]> 00 00 00 00 [L2]> 00 00 00 00 [L3]> 00 00 00 00 [L4]> 
get(4) -> data+12
Buffer: 00 00 00 00 [L1]> 00 00 00 00 [L2]> 00 00 00 00 [L3]> (L4=tail+4) 
Test msgb_hexdump
Buffer: (L1=data-124) 00 00 00 00 00 00 00 00 [L2]> 00 00 00 00 [L3]> (L4=tail+4) 
Buffer: (L1=data-124) 00 00 00 00 00 00 00 00 [L2]> (L3+8) 00 00 00 00 (L4=tail+4) 
Buffer: (L1=data-124) 00 00 00 00 00 00 00 00 [L2]> 00 00 00 00 (L3 out of range) (L4=tail+4) 
Testing msgb_copy
Src: [L1]> 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 [L2]> 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 [L3]> 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 39 3a 3b [L4]> 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f 
Dst: [L1]> 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 [L2]> 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 [L3]> 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 39 3a 3b [L4]> 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f 
msgb(%p): Sub area is not fully contained in the msg data
msgb(%p): Sub area is not fully contained in the msg data
msgb(%p): Sub area is not fully contained in the msg data
msgb(%p): Negative sizes are not allowed
msgb(%p): Negative sizes are not allowed
Testing msgb_resize_area
Original: [L1]> 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 [L2]> 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 [L3]> 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 39 3a 3b [L4]> 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f 
Extended: [L1]> 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 [L2]> 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [L3]> 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 39 3a 3b [L4]> 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f 
Shrinked: [L1]> 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 [L2]> 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [L3]> 28 29 2a 2b 2c 2d 2e 2f 30 31 [L4]> 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f 
Success.