TCP/IP Illustrated

Appendix A. Solutions to Selected Exercises

Chapter 1

1.2 SLIP drivers execute at spltty (Figure 1.13), which must be a priority lower than or equal to splimp and must be a priority higher than splnet. Therefore the SLIP drivers are blocked from interrupting.

Chapter 2

2.1 The M_EXT flag is a property of the mbuf itself, not a property of the packet described by the mbuf.

2.2 The caller asks for more than 100 (MHLEN) contiguous bytes.

2.3 This is infeasible since clusters can be pointed to by multiple mbufs (Section 2.9). Also, there is no room in a cluster for a back pointer (Exercise 2.4).

2.4 In the macros MCLALLOC and MCLFREE in <sys/mbuf.h> we see that the reference count is an array named mclrefcnt. This ...