Linux Kernel Networking Matthew Caesar（Linux内核网络马修·凯撒）.pdf

Linux Kernel Networking Raoul Rivas Kernel vs Application Programming ● No memory protection ● Memory Protection ● We share memory with ● Segmentation Fault devices, scheduler ● Preemption ● Sometimes no preemption ● Scheduling isnt our ● Can hog the CPU responsibility ● Concurrency is difficult ● Signals (Control-C) ● No libraries ● Libraries ● Printf, fopen ● Security Descriptors ● No security descriptors ● In Linux everything is a file ● In Linux no access to files descriptor ● Direct access to hardware ● Access to hardware as files Outline ● User Space and Kernel Space ● Running Context in the Kernel ● Locking ● Deferring Work ● Linux Network Architecture ● Sockets, Families and Protocols ● Packet Creation ● Fragmentation and Routing ● Data Link Layer and Packet Scheduling ● High Performance Networking System Calls ● A system call is an interrupt 0xFFFF50 Kernel Space ● syscall(number, Syscall sys_write() arguments) table ● The kernel runs in a different address space INT Copy_from_user() ● Data must be copied back 0x80 and forth syscall(WRITE, ptr, size)