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f3e7ed2b61
Assign a random MAC to an ethernet interface if one was not provided on the command line. This became pressing when distros started bringing interfaces up before assigning IPs to them. The previous pattern of assigning an IP then bringing it up allowed the MAC to be generated from the first IP assigned. However, once the thing is up, it's probably a bad idea to change the MAC, so the MAC stayed initialized to fe:fd:0:0:0:0. Now, if there is no MAC from the command line, one is generated. We use the microseconds from gettimeofday (20 bits), plus the low 12 bits of the pid to seed the random number generator. random() is called twice, with 16 bits of each result used. I didn't want to have to try to fill in 32 bits optimally given an arbitrary RAND_MAX, so I just assume that it is greater than 65536 and use 16 bits of each random() return. There is also a bit of reformatting and whitespace cleanup here. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
56 lines
1.7 KiB
C
56 lines
1.7 KiB
C
/*
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* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
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* Licensed under the GPL
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*/
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#ifndef __UM_NET_USER_H__
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#define __UM_NET_USER_H__
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#define ETH_ADDR_LEN (6)
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#define ETH_HEADER_ETHERTAP (16)
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#define ETH_HEADER_OTHER (14)
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#define ETH_MAX_PACKET (1500)
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#define UML_NET_VERSION (4)
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struct net_user_info {
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void (*init)(void *, void *);
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int (*open)(void *);
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void (*close)(int, void *);
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void (*remove)(void *);
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int (*set_mtu)(int mtu, void *);
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void (*add_address)(unsigned char *, unsigned char *, void *);
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void (*delete_address)(unsigned char *, unsigned char *, void *);
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int max_packet;
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};
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extern void ether_user_init(void *data, void *dev);
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extern void dev_ip_addr(void *d, unsigned char *bin_buf);
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extern void iter_addresses(void *d, void (*cb)(unsigned char *,
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unsigned char *, void *),
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void *arg);
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extern void *get_output_buffer(int *len_out);
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extern void free_output_buffer(void *buffer);
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extern int tap_open_common(void *dev, char *gate_addr);
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extern void tap_check_ips(char *gate_addr, unsigned char *eth_addr);
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extern void read_output(int fd, char *output_out, int len);
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extern int net_read(int fd, void *buf, int len);
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extern int net_recvfrom(int fd, void *buf, int len);
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extern int net_write(int fd, void *buf, int len);
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extern int net_send(int fd, void *buf, int len);
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extern int net_sendto(int fd, void *buf, int len, void *to, int sock_len);
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extern void open_addr(unsigned char *addr, unsigned char *netmask, void *arg);
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extern void close_addr(unsigned char *addr, unsigned char *netmask, void *arg);
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extern char *split_if_spec(char *str, ...);
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extern int dev_netmask(void *d, void *m);
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extern void random_mac(unsigned char *addr);
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#endif
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