{"id":598,"date":"2010-06-28T15:43:46","date_gmt":"2010-06-28T07:43:46","guid":{"rendered":"http:\/\/www.kumouse.com\/?p=598"},"modified":"2010-06-28T15:43:46","modified_gmt":"2010-06-28T07:43:46","slug":"ip-%e9%80%89%e8%b7%af%e8%a1%a8-%e5%92%8c-%e9%80%89%e8%b7%af%e7%ae%97%e6%b3%95","status":"publish","type":"post","link":"https:\/\/www.kumouse.com\/?p=598","title":{"rendered":"IP \u9009\u8def\u8868 \u548c \u9009\u8def\u7b97\u6cd5"},"content":{"rendered":"

1 \u5f15\u8a00
\n\u8ba8\u8bba\u9009\u62e9\u8def\u7531\u7684\u7ec6\u8282\uff0c\u9009\u8def\u8868\u7684\u7ed3\u6784\uff0c\u4ee5\u53ca\u5b9e\u73b0\u7b97\u6cd5\uff0c\u8def\u7531\u5982\u4f55\u4f7f\u7528\u5b50\u7f51\u63a9\u7801\uff0c\u5982\u4f55\u533a\u5206\u7f51\u7edc\u8def\u7531\u5b50\u7f51\u8def\u7531\u4ee5\u53ca\u4e3b\u673a\u8def\u7531<\/p>\n

2 \u8def\u7531\u7ef4\u62a4\u548c\u67e5\u627e
\n\u5e94\u5f53\u9009\u62e9\u80fd\u4f7f\u67e5\u627e\u8def\u7531\u82b1\u8d39\u6700\u5c0f\u7684IP\u6570\u636e\u7ed3\u6784\u548c\u7b97\u6cd5\uff0c\u7ef4\u62a4\u8def\u7531\u7684\u82b1\u8d39\u5219\u5e76\u4e0d\u90a3\u4e48\u91cd\u8981
\n\u5229\u7528\u6876\u6563\u5217\uff08bucket hashing\uff09\u8fc5\u901f\u627e\u5230\u6b63\u786e\u7684\u6563\u5217\u8868\u5143<\/p>\n

3 \u9009\u8def\u8868\u7ed3\u6784
\n\u4fdd\u5b58\u8def\u7531\u7684\u4e3b\u8981\u6570\u636e\u7ed3\u6784\u662f\u6570\u7ec4\u3002\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u6563\u5217\u8868\u5143\uff0c\u5e76\u5305\u542b\u4e00\u4e2a\u6307\u9488\uff0c\u6307\u5411\u88ab\u88c5\u5165\u8fd9\u4e2a\u6563\u5217\u8868\u5143\u4e2d\u7684\u901a\u4e3b\u76ee\u7684\u7ad9\u7684\u8def\u7531\u8bb0\u5f55\u94fe\u8868\u3002\u8868\u4e2d\u6bcf\u4e2a\u8bb0\u5f55\u5305\u542b\u4e00\u4e2aIP\u76ee\u7684\u5730\u5740\uff0c\u5b50\u7f51\u63a9\u7801\uff0c\u4e0b\u4e00\u8df3\u5730\u5740\uff0c\u7528\u4e8e\u5411\u4e0b\u4e00\u8df3\u5730\u5740\u53d1\u9001\u6570\u636e\u7684\u7f51\u7edc\u63a5\u53e3\uff0c\u4ee5\u53ca\u5176\u4ed6\u7684\u8def\u7531\u7ba1\u7406\u4e2d\u4f7f\u7528\u7684\u4fe1\u606f\u3002\u7531\u4e8eIP\u9884\u5148\u5e76\u4e0d\u77e5\u9053\u5b50\u7f51\u63a9\u7801\uff0c\u5b83\u516c\u4f7f\u7528IP\u76ee\u7684\u5730\u5740\u7684\u7f51\u7edc\u90e8\u5206\u8ba1\u7b97\u6563\u5217\u51fd\u6570\uff0c\u5728\u4e00\u4e2a\u94fe\u8868\u4e2d\u67e5\u627e\u8868\u9879\u65f6\uff0c\u4f7f\u7528\u7684\u662f\u5b8c\u6574\u7684\u76ee\u7684\u5730\u5740\u6765\u8fdb\u884c\u6bd4\u8f83\u3002<\/p>\n

4 \u9009\u8def\u8868\u6570\u636e\u7ed3\u6784<\/p>\n

\/* route.h – RTFREE *\/<\/p>\n

\/* \u8def\u7531\u8868\u9879 *\/
\nstruct route {
\n\tIPaddr\trt_net;\t\t\/* \u8def\u7531\u7684\u76ee\u7684\u5730\u5740\t*\/
\n\tIPaddr\trt_mask;\t\/* \u8def\u7531\u7684\u63a9\u7801\t\t\t*\/
\n\tIPaddr\trt_gw;\t\t\/* \u4e0b\u4e00\u8df3\u7684IP\t\t*\/
\n\tu_short\trt_metric;\t\/* \u8ddd\u79bb\u5ea6\u91cf\t\t*\/
\n\tu_short\trt_ifnum;\t\/* \u63a5\u53e3\u7684\u5e8f\u53f7\t\t*\/
\n\tshort\trt_key;\t\t\/* \u6392\u5e8f\u5173\u952e\u5b57\t\t*\/
\n\tshort\trt_ttl;\t\t\/* \u751f\u5b58\u65f6\u95f4\uff08\u79d2\uff09\t*\/
\n\tstruct\troute *rt_next;\t\/* \u54c8\u5e0c\u503c\u6307\u5411\u4e0b\u4e00\u4e2a\u6761\u76ee\t*\/
\n\/* stats *\/
\n\tint\trt_refcnt;\t\/* \u5f15\u7528\u8ba1\u6570\t\t*\/
\n\tint\trt_usecnt;\t\/* \u8bb0\u5f55\u8be5\u8def\u7531\u4f7f\u7528\u7684\u6b21\u6570\t*\/
\n};<\/p>\n

\/* \u8def\u7531\u8868\u7684\u5168\u5c40\u6570\u636e *\/
\nstruct rtinfo {
\n\tstruct\troute\t*ri_default;\t\/* \u5305\u542b\u9ed8\u8ba4\u8def\u7531\u7684\u4e0b\u4e00\u8df3\u5730\u5740 *\/
\n\tint\t\tri_bpool;\t\/* \u7ed3\u70b9\u7684\u5730\u5740??? Route.ri_bpool = mkpool(sizeof(struct route), RT_BPSIZE) \u73b0\u5728\u8fd8\u4e0d\u592a\u660e\u767d *\/
\n\tBool\t\tri_valid;\t\/* \u6b64\u8def\u7531\u7684\u6570\u636e\u7ed3\u6784\u662f\u5426\u88ab\u521d\u59cb\u5316 *\/
\n\tint\t\tri_mutex;\t\/* \u4e92\u65a5\u4fe1\u53f7 *\/
\n};<\/p>\n

#define\tRT_DEFAULT ip_anyaddr\t\/* \u9ed8\u8ba4\u7684\u7f51\u7edc\u5730\u5740 \u51680\t\t*\/
\n#define\tRT_LOOPBACK ip_loopback\t\/* \u56de\u73af\u5730\u5740\t\t\t*\/
\n#define\tRT_TSIZE\t512\t\/* \u6563\u5217\u8868\u957f\u5ea6??-these are pointers; it’s cheap\t*\/
\n#define\tRT_INF\t\t999\t\/* \u8def\u7531\u6c38\u4e0d\u8d85\u65f6\t\t*\/<\/p>\n

#define\tRTM_INF\t\t16\t\/* \u4e00\u4e2a\u6700\u5927\u8ddd\u79bb\u5ea6\u91cf – an infinite metric\t*\/<\/p>\n

\/* rtget\uff08\uff09\u7684\u7b2c\u4e8c\u4e2a\u53c2\u6570… *\/<\/p>\n

#define\tRTF_REMOTE\t0\t\/* \u8fdc\u7a0b\u4e3b\u673a\u4ea7\u751f\u7684\u901a\u4fe1\t*\/
\n#define\tRTF_LOCAL\t1\t\/* \u672c\u5730\u4ea7\u751f\u7684\u901a\u4fe1\t\t*\/<\/p>\n

#define\tRT_BPSIZE\t100\t\/* \u8def\u7531\u7684\u6700\u5927\u6570\u91cf\t\t\t*\/<\/p>\n

\/* RTFREE – \u5220\u9664\u4e00\u4e2a\u8def\u7531\u5f15\u7528\uff08\u5047\u5b9a\u6301\u6709ri_mutex\uff09\t\t*\/<\/p>\n

#define\tRTFREE(prt)
\n\tif (–prt->rt_refcnt <= 0) {\t\t\t\n\t\tfreebuf(prt);\t\t\t\t\n\t}\n\nextern\tstruct\trtinfo\tRoute;\nextern\tstruct\troute\t*rttable[];\n\nint rtadd(IPaddr, IPaddr, IPaddr, unsigned, unsigned, unsigned);\nint rtdel(IPaddr, IPaddr), rthash(IPaddr), rtfree(struct route *);\nstruct route *rtget(IPaddr, Bool);\nvoid rtinit(void);\nvoid ipredirect(struct ep *, unsigned, struct route *);\nvoid ipdbc(unsigned, struct ep *, struct route *);\n\n\n5 \u8def\u7531\u7684\u751f\u6210\u6e90\u53ca\u4fdd\u6301\u65f6\u95f4\n\u9009\u8def\u8868\u9879\u7684\u6613\u5931\u6027\u4e0e\u5b83\u7684\u6765\u6e90\u6709\u5173(\u4ece\u5907\u4efd\u5b58\u50a8\u5668\u4e2d\u5f97\u5230,ICMP\u6216\u9009\u8def\u534f\u8bae,\u7f51\u7edc\u7ba1\u7406\u5458\u624b\u52a8\u64cd\u4f5c),\u4f46\u4e3a\u4e86\u6392\u9664\u7f51\u7edc\u4e2d\u7684\u8def\u7531\u95ee\u9898,\u7ba1\u7406\u5458\u53ef\u4ee5\u63a8\u7ffb\u4efb\u4f55\u8def\u7531\u5e76\u5efa\u7acb\u4e0d\u53ef\u6539\u53d8\u7684\u6c38\u4e45\u7684\u8def\u7531\n\n6 \u4e3a\u6570\u636e\u62a5\u9009\u62e9\u8def\u7531\n6.1 \u5b9e\u7528\u8fc7\u7a0b\n\/* netnum.c - netnum *\/\n\n#include
\n#include
\n#include <\/p>\n

\/*————————————————————————
\n * netnum – \u8ba1\u7b97\u4e00\u4e2a\u7ed9\u5b9aIP \u5730\u5740\u7684\u7f51\u7edc\u90e8\u5206
\n *————————————————————————
\n *\/
\nIPaddr
\nnetnum(IPaddr ipa)
\n{
\n\tIPaddr\tmask = ~0;<\/p>\n

\tif (IP_CLASSA(ipa)) mask = hl2net(0xff000000);
\n\tif (IP_CLASSB(ipa)) mask = hl2net(0xffff0000);
\n\tif (IP_CLASSC(ipa)) mask = hl2net(0xffffff00);
\n\treturn ipa & mask;\t\t\t\/* \u8fd4\u56de\u4e00\u4e2a\u4e3b\u673a\u5730\u5740\u5b57\u8282\u4e3a\u51680\u7684\u5730\u5740*\/
\n}<\/p>\n

\/* netmatch.c – netmatch *\/<\/p>\n

#include
\n#include
\n#include <\/p>\n

\/*————————————————————————
\n * netmatch – \u662f\u5426\u662f\u8fd9\u4e2a\u7f51\u7edc\u4e0a\u7684\u5730\u5740?
\n *————————————————————————
\n *\/
\nBool
\nnetmatch(IPaddr dst, IPaddr net, IPaddr mask, Bool islocal)
\n{
\n\tif ((dst & mask) != (net & mask))\t\t\/* \u76ee\u7684\u5730\u5740\u4e0e\u9009\u8def\u8868\u4e2d\u5730\u5740\u6bd4\u8f83*\/
\n\t\treturn FALSE;
\n\t\/*
\n\t * \u6e90\u5730\u5740\u4e3a\u672c\u5730\u53ef\u4ee5\u53ea\u5339\u914d\u5355\u64ad\u5730\u5740 (\u4e3b\u673a\u4e3a\u8def\u7531)
\n\t *\/
\n\tif (islocal)\t\t\t\t\t\/* \u5982\u679c\u662f\u672c\u5730*\/
\n\t\tif (isbrc(dst) || IP_CLASSD(dst))\t\/* \u5982\u679c\u76ee\u7684\u5730\u5740\u4e0d\u662f\u5e7f\u64ad\u5730\u5740,\u6216\u4e0d\u662fD\u7c7b*\/
\n\t\t\treturn mask != ip_maskall;\t\/* \u5e76\u4e14\u63a9\u7801\u4e0d\u4e3a\u51681,\u5219\u8fd4\u56de\u771f,\u5426\u5219\u4e3a\u5047*\/
\n\treturn TRUE;
\n}<\/p>\n

\/* netmask.c – netmask *\/<\/p>\n

#include
\n#include
\n#include <\/p>\n

IPaddr netnum(IPaddr);<\/p>\n

\/*————————————————————————
\n * netmask – \u4e3a\u7ed9\u5b9a\u7f51\u7edc\u8bbe\u5b9a\u9ed8\u8ba4\u63a9\u7801
\n *————————————————————————
\n *\/
\nIPaddr
\nnetmask(IPaddr net)
\n{
\n\tIPaddr\tnetpart;
\n\tint\ti;<\/p>\n

\tif (net == 0)\t\t\t\t\t\/* \u76ee\u7684\u5730\u5740\u4e3a\u51680,\u5219\u4f7f\u7528\u9ed8\u8ba4\u8def\u7531,\u8fd4\u56de\u51680\u63a9\u7801*\/
\n\t\treturn net;
\n\t\/* \u7f51\u7edc\u5339\u914d\u68c0\u67e5 (\u5b50\u7f51) *\/<\/p>\n

\tnetpart = netnum(net);\t\t\t\t\/* \u63d0\u53d6\u51fa\u7f51\u7edc\u90e8\u5206*\/
\n\tfor (i=0; i
\n#include
\n#include <\/p>\n

\/*————————————————————————
\n * rthash – \u8ba1\u7b97\u7f51\u7edc\u7684\u54c8\u5e0c\u503c
\n *————————————————————————
\n *\/
\nint
\nrthash(IPaddr net)
\n{
\n\tint\t\tbc = IP_ALEN;\t\/* # \u5b57\u8282\u6570\t*\/
\n\tunsigned int\thv = 0;\t\t\/* \u54c8\u5e0c\u503c\t\t*\/<\/p>\n

\tif (IP_CLASSA(net)) bc = 1;
\n\telse if (IP_CLASSB(net)) bc = 2;
\n\telse if (IP_CLASSC(net)) bc = 3;
\n\telse if (IP_CLASSD(net))
\n\t\treturn ((net>>24) & 0xf0) % RT_TSIZE;\t\/* D\u7c7b\u524d4\u6bd4\u7279\u4e5816\u518d\u4e0e\u6563\u5217\u8868\u957f\u5ea6\u53d6\u4f59\u6570*\/
\n\twhile (bc–)
\n\t\thv += ((char *)&net)[bc] & 0xff;\t\t\/* \u6bcf8\u4f4d\u76f8\u52a0*\/
\n\treturn hv % RT_TSIZE;\t\t\t\t\/* \u8fd4\u56de\u9664\u4ee5\u6563\u5217\u957f\u5ea6\u540e\u7684\u4f59\u6570*\/
\n}<\/p>\n

6.2 \u83b7\u5f97\u4e00\u4e2a\u8def\u7531<\/p>\n

\/* rtget.c – rtget *\/<\/p>\n

#include
\n#include
\n#include <\/p>\n

\/*————————————————————————
\n * rtget – \u83b7\u5f97\u4e00\u4e2a\u7ed9\u5b9a\u7684IP\u5730\u5740\u7684\u8def\u7531
\n *————————————————————————
\n *\/
\nstruct route *
\nrtget(IPaddr dest, Bool local)
\n{
\n\tstruct\troute\t*prt;
\n\tint\t\thv;<\/p>\n

\tif (!Route.ri_valid)\t\t\t\/* \u5982\u679c\u8def\u7531\u7684\u6570\u636e\u7ed3\u6784\u6ca1\u88ab\u521d\u59cb\u5316\u5219\u5e94\u8be5\u5148\u521d\u59cb\u5316*\/
\n\t\trtinit();
\n\twait(Route.ri_mutex);\t\t\t\/* \u7b49\u5f85\u4fe1\u53f7\u4e92\u65a5\u91cf*\/
\n\thv = rthash(dest);\t\t\t\/* \u8ba1\u7b97\u54c8\u5e0c\u503c*\/
\n\tfor (prt=rttable[hv]; prt; prt=prt->rt_next) {
\n\t\tif (prt->rt_ttl <= 0)\n\t\t\tcontinue;\t\t\/* \u8def\u7531\u8fc7\u671f *\/\n\t\tif (netmatch(dest, prt->rt_net, prt->rt_mask, local))\t\/* \u5982\u679c\u7f51\u7edc\u5730\u5740\u5339\u914d*\/
\n\t\t\tif (prt->rt_metric < RTM_INF)\t\t\/* \u5e76\u4e14\u8ddd\u79bb\u91cf\u5ea6\u5c0f\u4e8e\u6700\u5927\u7684\u91cf\u5ea6*\/\n\t\t\t\tbreak;\t\t\/* \u5219\u9000\u51fafor\u5faa\u73af*\/\n\t}\n\tif (prt == 0)\t\t\t\t\/* \u5982\u679c\u6ca1\u6709\u627e\u5230\u5339\u914d\u7684\u7f51\u7edc\u5730\u5740*\/\n\t\tprt = Route.ri_default;\t\/* \u4f7f\u7528\u9ed8\u8ba4\u8def\u7531 *\/\n\tif (prt != 0 && prt->rt_metric >= RTM_INF)\t\/*\u5982\u679c\u627e\u5230\u5339\u914d\u4e14\u8def\u79bb\u91cf\u5ea6\u5927\u4e8e\u6700\u5927\u7684\u91cf\u5ea6*\/
\n\t\tprt = 0;\t\t\t\t\t\/* prt\u6307\u54110*\/
\n\tif (prt) {
\n\t\tprt->rt_refcnt++;\t\t\t\/* \u5f15\u7528\u8ba1\u6570\u52a01*\/
\n\t\tprt->rt_usecnt++;\t\t\t\/* \u7edf\u8ba1\u8ba1\u6570\u52a01*\/
\n\t}
\n\tsignal(Route.ri_mutex);\t\t\t\t\/* \u91ca\u653e\u4e92\u65a5\u91cf*\/
\n\treturn prt;
\n}<\/p>\n

6.3 \u6570\u636e\u7ed3\u6784\u521d\u59cb\u5316<\/p>\n

\/* rtinit.c – rtinit *\/<\/p>\n

#include
\n#include
\n#include
\n#include <\/p>\n

struct\trtinfo\tRoute;
\nstruct\troute\t*rttable[RT_TSIZE];<\/p>\n

\/*————————————————————————
\n * rtinit – \u521d\u59cb\u5316\u8def\u7531\u8868
\n *————————————————————————
\n *\/
\nvoid
\nrtinit(void)
\n{
\n\tint i;<\/p>\n

\tfor (i=0; i
\n#include
\n#include \n#include <\/p>\n

extern\tBool\tdorip;\t\t\/* TRUE \u5982\u679c\u6211\u4eec\u6b63\u5728\u8fd0\u884c\u7684RIP\u8f93\u51fa\t*\/
\nextern\tint\trippid;\t\t\/* \u8f93\u51fa\u7684RIP\u7684pid\uff0c\u5982\u679c\u8fd0\u884c\t*\/<\/p>\n

\/*————————————————————————
\n * rttimer – \u66f4\u65b0TTLS\u53ca\u5220\u9664\u8fc7\u671f\u8def\u7531
\n *————————————————————————
\n *\/
\nvoid
\nrttimer(unsigned int delta)
\n{
\n\tstruct\troute\t*prt, *prev;
\n\tBool\t\tripnotify;
\n\tint\t\ti;<\/p>\n

\tif (!Route.ri_valid)\t\t\/* \u8def\u7531\u672a\u88ab\u521d\u59cb\u5316\u5219\u8fd4\u56de*\/
\n\t\treturn;
\n\twait(Route.ri_mutex);\t\t\/* \u7b49\u5f85\u4e92\u65a5\u91cf*\/<\/p>\n

\tripnotify = FALSE;\t\t\/* RIP\u901a\u77e5\u5173\u95ed*\/
\n\tfor (i=0; irt_ttl != RT_INF)\t\/* \u5982\u679c\u751f\u5b58\u65f6\u95f4\u4e0d\u7b49\u4e8e\u6c38\u4e45*\/
\n\t\t\t\tprt->rt_ttl -= delta;\t\/* \u751f\u5b58\u65f6\u95f4\u51cf\u53bb\u76f8\u5e94\u7684\u65f6\u95f4*\/
\n\t\t\tif (prt->rt_ttl <= 0) {\t\t\/* \u5982\u679c\u751f\u5b58\u65f6\u95f4\u5c0f\u4e8e\u7b49\u4e8e0*\/\n#ifdef\tRIP\t\t\/* \u6761\u4ef6\u7f16\u8bd1,\u5f53\u6253\u5f00RIP\u65f6*\/\n\t\t\t\tif (dorip && prt->rt_metric < RTM_INF) {\t\/*RIP\u6253\u5f00\u4e14\u8ddd\u79bb\u5c0f\u4e8e\u6700\u5927\u8ddd\u79bb*\/\n\t\t\t\t\tprt->rt_metric = RTM_INF;\t\/* \u8bbe\u7f6e\u8ddd\u79bb\u4e3a\u6700\u5927\u8ddd\u79bb*\/
\n\t\t\t\t\tprt->rt_ttl = RIPZTIME;\t\t\/* \u751f\u5b58\u65f6\u95f4\u4e3a\u65e0\u7a77*\/
\n\t\t\t\t\tripnotify = TRUE;\t\t\/* \u6253\u5f00RIP\u901a\u77e5*\/
\n\t\t\t\t\tcontinue;
\n\t\t\t\t}
\n#endif\t\/* RIP *\/
\n\t\t\t\tif (prev) {\t\t\/*\u5982\u679cprev\u4e0d\u4e3a\u7a7a,\u5220\u9664prt\u6307\u5411\u7684\u8868\u9879*\/
\n\t\t\t\t\tprev->rt_next = prt->rt_next;
\n\t\t\t\t\tRTFREE(prt);
\n\t\t\t\t\tprt = prev->rt_next;
\n\t\t\t\t} else {\t\t\/*\u5426\u5219\u8bf4\u660eprt\u5c31\u662f\u7b2c\u4e00\u4e2a\u8868\u9879*\/
\n\t\t\t\t\trttable[i] = prt->rt_next;\t\/*\u5220\u9664\u7b2c\u4e00\u4e2a\u8868\u9879*\/
\n\t\t\t\t\tRTFREE(prt);
\n\t\t\t\t\tprt = rttable[i];
\n\t\t\t\t}
\n\t\t\t\tcontinue;
\n\t\t\t}
\n\t\t\tprev = prt;\t\t\/* \u6307\u5411\u4e0b\u4e00\u4e2a*\/
\n\t\t\tprt = prt->rt_next;\t\/* \u6307\u5411\u4e0b\u4e00\u4e2a*\/
\n\t\t}
\n\t}
\n\tprt = Route.ri_default;\t\t\/* \u4f7f\u7528\u9ed8\u8ba4\u8def\u7531*\/
\n\tif (prt && (prt->rt_ttlrt_ttl -= delta) <= 0) { \/* \u9ed8\u8ba4\u8def\u7531\u4e0d\u5408\u9002*\/\n#ifdef\tRIP\n\t\tif (dorip && prt->rt_metric < RTM_INF) {\t\/* RIP\u6253\u5f00\u4e14\u8ddd\u79bb\u5c0f\u4e8e\u6700\u5927\u8ddd\u79bb *\/\n\t\t\tprt->rt_metric = RTM_INF;\t\/* \u8ddd\u79bb\u4e3a\u6700\u5927\u8ddd\u79bb\u91cf\u5ea6 *\/
\n\t\t\tprt->rt_ttl = RIPZTIME;\t\t\/* \u751f\u5b58\u65f6\u95f4\u4e3a\u65e0\u7a77*\/
\n\t\t} else
\n#endif\t\/* RIP *\/
\n\t\t{
\n\t\t\tRTFREE(Route.ri_default);\t\t\/* \u91ca\u653e\u9ed8\u8ba4\u8def\u7531 *\/
\n\t\t\tRoute.ri_default = 0;\t\t\/* \u6e05\u9664\u9ed8\u8ba4\u8def\u7531\u6307\u9488*\/
\n\t\t}
\n\t}
\n\tsignal(Route.ri_mutex);\t\t\/* \u91ca\u653e\u4e92\u65a5\u91cf*\/
\n#ifdef\tRIP
\n\tif (dorip && ripnotify)\t\t\/* RIP\u6253\u5f00\u5e76\u4e14RIP\u901a\u77e5\u6253\u5f00*\/
\n\t\tsend(rippid, 0);\t\/* \u53d1\u9001\u4efb\u4f55\u4e1c\u897f\uff0c\u4f46\u8d85\u65f6\t*\/
\n#endif\t\/* RIP *\/
\n\treturn;
\n}<\/p>\n

7.1 \u589e\u52a0\u8def\u7531<\/p>\n

\/* rtadd.c – rtadd *\/<\/p>\n

#include
\n#include
\n#include \n#include <\/p>\n

struct\troute *rtnew(IPaddr, IPaddr, IPaddr, unsigned,unsigned,unsigned);
\nvoid rtinit(void);
\nint rthash(IPaddr);<\/p>\n

\/*————————————————————————
\n * rtadd – \u6dfb\u52a0\u4e00\u4e2a\u8def\u7531\u5230\u8def\u7531\u8868
\n *————————————————————————
\n *\/
\nint
\nrtadd(IPaddr net, IPaddr mask, IPaddr gw, unsigned metric,
\n\tunsigned intf, unsigned ttl)
\n{
\n\tstruct\troute\t*prt, *srt, *prev;
\n\tBool\t\tisdup;
\n\tint\t\thv, i;<\/p>\n

\tif (!Route.ri_valid)\t\t\/* \u521d\u59cb\u5316*\/
\n\t\trtinit();<\/p>\n

\tprt = rtnew(net, mask, gw, metric, intf, ttl);\t\t\/* \u5efa\u7acb\u65b0\u7684\u7ed3\u70b9*\/
\n\tif (prt == (struct route *)SYSERR)\t\t\t\/* \u5206\u914d\u5931\u8d25\u5219\u8fd4\u56de\u9519\u8bef*\/
\n\t\treturn SYSERR;<\/p>\n

\t\/* \u8ba1\u7b97\uff0c\u8def\u7531\u5728\u961f\u5217\u4e2d\u7684\u952e *\/
\n\tprt->rt_key = 0;
\n\tfor (i=0; i<32; ++i)\n\t\tprt->rt_key += (mask >> i) & 1;
\n\twait(Route.ri_mutex);\t\t\/* \u7b49\u5f85\u4e92\u65a5\u91cf*\/<\/p>\n

\t\/* \u9ed8\u8ba4\u8def\u7531\u7684\u7279\u6b8a\u60c5\u51b5 *\/
\n\tif (net == RT_DEFAULT) {\t\t\/* \u5982\u679c\u7f51\u7edc\u5730\u5740\u4e3a\u4efb\u610f,\u51680*\/
\n\t\tif (Route.ri_default)\t\/* \u9ed8\u8ba4\u8def\u7531\u4e0d\u4e3a\u7a7a*\/
\n\t\t\tRTFREE(Route.ri_default);\t\/* \u91ca\u653e\u9ed8\u8ba4\u8def\u7531*\/
\n\t\tRoute.ri_default = prt;\t\t\/* \u7528\u65b0\u7684\u8def\u7531\u4ee3\u66ff*\/
\n\t\tsignal(Route.ri_mutex);\t\t\/* \u91ca\u653e\u4e92\u65a5\u91cf*\/
\n\t\treturn OK;
\n\t}
\n\tprev = NULL;
\n\thv = rthash(net);\t\/* \u8ba1\u7b97\u54c8\u5e0c\u503c*\/
\n\tisdup = FALSE;\t\t\/* \u662f\u5426\u6709\u76f8\u540c\u5730\u5740\u7684\u8def\u7531\u8868\u9879*\/
\n\t \/* \u67e5\u627e\u662f\u5426\u6709\u76f8\u540c\u7684\u8def\u7531*\/
\n\tfor (srt=rttable[hv]; srt; srt = srt->rt_next) {\t\/*srt \u4e3a\u7a7a\u5219\u9000\u51fafor*\/
\n\t\tif (prt->rt_key > srt->rt_key)\t\t\/* *\/
\n\t\t\tbreak;
\n\t\tif (srt->rt_net == prt->rt_net &&\t\/* \u7f51\u7edc\u5730\u5740\u548c\u63a9\u7801\u5747\u76f8\u540c,\u627e\u5230\u76f8\u540c\u7684\u5730\u5740\u7684\u8def\u7531*\/
\n\t \t srt->rt_mask == prt->rt_mask) {
\n\t\t\tisdup = TRUE;\t\t\t\/* isdup\u4e3a\u771f*\/
\n\t\t\tbreak;
\n\t\t}
\n\t\tprev = srt;
\n\t}
\n\tif (isdup) {\t\t\/* isdup\u4e3a\u771f,\u8bf4\u660e\u6709\u76f8\u540c\u7684\u8def\u7531\u8868\u9879*\/
\n\t\tstruct\troute\t*tmprt;<\/p>\n

\t\tif (srt->rt_gw == prt->rt_gw) {\t\t\/* \u6e90\u8def\u7531\u8868\u4e0e\u65b0\u8def\u7531\u8868\u7684\u4e0b\u4e00\u8df3\u76f8\u540c *\/
\n\t\t\t\/* \u66f4\u65b0\u65b0\u7531\u8868 *\/
\n#ifdef\tRIP\t\t\/* RIP\u6253\u5f00\u7684\u60c5\u51b5,\u4e0a\u8fb9\u8bf4\u8fc7\u5f88\u591a\u56de\u4e86,\u4e0b\u8fb9\u4e0d\u518d\u591a\u8bf4*\/
\n\t\t\tif (dorip) {
\n\t\t\t\tsrt->rt_ttl = ttl;
\n\t\t\t\tif (srt->rt_metric != metric) {
\n\t\t\t\t\tif (metric == RTM_INF)
\n\t\t\t\t\t\tsrt->rt_ttl = RIPZTIME;
\n\t\t\t\t\tsend(rippid, 0);
\n\t\t\t\t}
\n\t\t\t}
\n#endif\t\/* RIP *\/
\n\t\t\tsrt->rt_metric = metric;\t\t\/* \u66f4\u65b0\u8ddd\u79bb\u91cf\u5ea6*\/
\n\t\t\tRTFREE(prt);\t\t\t\/* \u91ca\u653eprt*\/
\n\t\t\tsignal(Route.ri_mutex);\t\t\/* \u91ca\u653e\u4e92\u65a5\u91cf*\/
\n\t\t\treturn OK;
\n\t\t}
\n\t\t\/* else, someone else has a route there… *\/
\n\t\tif (srt->rt_metric <= prt->rt_metric) {\t\/* \u6e90\u8def\u7531\u6bd4\u65b0\u8def\u7531\u5177\u6709\u66f4\u5c0f\u7684\u8ddd\u79bb\u5e76\u4e14\u4e0b\u4e00\u8df3\u5730\u5740\u4e0d\u540c*\/
\n\t\t\t\/* \u6ca1\u6709\u66f4\u597d\u7684\u8def\u7531\u7ebf\u8def,\u653e\u5f03\u65b0\u7684\u8def\u7531 *\/<\/p>\n

\t\t\tRTFREE(prt);
\n\t\t\tsignal(Route.ri_mutex);\t\/* \u91ca\u653e\u4e92\u65a5\u91cf*\/
\n\t\t\treturn OK;
\n\t\t}
\n#ifdef\tRIP
\n\t\telse if (dorip)
\n\t\t\tsend(rippid, 0);
\n#endif\t\/* RIP *\/
\n\t\ttmprt = srt;\t\t\/* \u6267\u884c\u5230\u8fd9\u91cc\u8bf4\u660e\u65b0\u8def\u7531\u66f4\u4f18,\u91ca\u653e\u65e7\u7684\u8def\u7531*\/
\n\t\tsrt = srt->rt_next;
\n\t\tRTFREE(tmprt);
\n\t}
\n#ifdef\tRIP
\n\telse if (dorip)
\n\t\tsend(rippid, 0);
\n#endif\t\/* RIP *\/
\n\tprt->rt_next = srt;\t\t\/* \u63d2\u5165\u65b0\u7684\u8def\u7531*\/
\n\tif (prev)\t\t\t\/* \u63d2\u5165\u5230\u94fe\u8868\u7684\u4e2d\u95f4*\/
\n\t\tprev->rt_next = prt;
\n\telse\t\t\t\t\/* \u63d2\u5165\u5230\u94fe\u8868\u7684\u5f00\u59cb*\/
\n\t\trttable[hv] = prt;
\n\tsignal(Route.ri_mutex);
\n\treturn OK;
\n}<\/p>\n

\u5efa\u7acb\u65b0\u7684\u7ed3\u70b9,\u5f88\u7b80\u5355\u4e0d\u591a\u8bf4\u4e86<\/p>\n

\/* rtnew.c – rtnew *\/<\/p>\n

#include
\n#include
\n#include <\/p>\n

\/*————————————————————————
\n * rtnew – \u521b\u5efa\u4e00\u4e2a\u8def\u7531\u7ed3\u6784
\n *————————————————————————
\n *\/
\nstruct route *
\nrtnew(IPaddr net, IPaddr mask, IPaddr gw, unsigned metric,
\n\tunsigned ifnum, unsigned ttl)
\n{
\n\tstruct\troute *prt;<\/p>\n

\tprt = (struct route *)getbuf(Route.ri_bpool);
\n\tif (prt == (struct route *)SYSERR) {
\n\t\tIpRoutingDiscards++;
\n\t\treturn (struct route *)SYSERR;
\n\t}<\/p>\n

\tprt->rt_net = net;
\n\tprt->rt_mask = mask;
\n\tprt->rt_gw = gw;
\n\tprt->rt_metric = metric;
\n\tprt->rt_ifnum = ifnum;
\n\tprt->rt_ttl = ttl;
\n\tprt->rt_refcnt = 1;\t\/* our caller *\/
\n\tprt->rt_usecnt = 0;
\n\tprt->rt_next = NULL;
\n\treturn prt;
\n}<\/p>\n

7.2 \u5220\u9664\u8def\u7531<\/p>\n

\/* rtdel.c – rtdel *\/<\/p>\n

#include
\n#include
\n#include <\/p>\n

\/*————————————————————————
\n * rtdel – \u5220\u9664\u7ed9\u5b9a\u7f51\u7edc\u7684\u8def\u7531\u548c\u63a9\u7801
\n *————————————————————————
\n *\/
\nint
\nrtdel(IPaddr net, IPaddr mask)
\n{
\n\tstruct\troute\t*prt, *prev;
\n\tint\t\thv, i;<\/p>\n

\tif (!Route.ri_valid)\t\t\/* \u672a\u88ab\u521d\u59cb\u5316\u5219\u8fd4\u56de\u51fa\u9519*\/
\n\t\treturn SYSERR;
\n\twait(Route.ri_mutex);\t\t\/* \u7b49\u5f85\u4e92\u65a5\u91cf*\/
\n\tif (Route.ri_default &&\t\t\/* \u9ed8\u8ba4\u8def\u7531\u5b58\u5728\u5e76\u4e14net\u53c2\u6570\u4e0e\u4e4b\u76f8\u540c,\u5219\u5220\u9664\u9ed8\u8ba4\u8def\u7531*\/
\n\t net == Route.ri_default->rt_net) {
\n\t\tRTFREE(Route.ri_default);
\n\t\tRoute.ri_default = 0;
\n\t\tsignal(Route.ri_mutex);
\n\t\treturn OK;
\n\t}
\n\thv = rthash(net);\t\t\/* \u8ba1\u7b97\u54c8\u5e0c\u503c*\/<\/p>\n

\tprev = NULL;
\n\t\/* \u67e5\u627e\u5339\u914d\u7684\u8def\u7531*\/
\n\tfor (prt = rttable[hv]; prt; prt = prt->rt_next) {
\n\t\tif (net == prt->rt_net &&
\n\t\t mask == prt->rt_mask)
\n\t\t\tbreak;
\n\t\tprev = prt;
\n\t}
\n\tif (prt == NULL) {\t\t\/* \u6ca1\u6709\u627e\u5230\u5339\u914d\u7684\u8def\u7531*\/
\n\t\tsignal(Route.ri_mutex);
\n\t\treturn SYSERR;
\n\t}
\n\tif (prev)\t\t\t\/* prev\u4e0d\u4e3a\u7a7a,\u8bf4\u660e\u5339\u914d\u7684\u8def\u7531\u5728\u94fe\u8868\u4e2d\u95f4,\u5e76\u5220\u9664\u7ed3\u70b9*\/
\n\t\tprev->rt_next = prt->rt_next;
\n\telse\t\t\t\t\/* \u8def\u7531\u5728\u94fe\u8868\u5f00\u5934*\/
\n\t\trttable[hv] = prt->rt_next;
\n\tRTFREE(prt);\t\t\t\/* \u91ca\u653e\u7ed3\u70b9*\/
\n\tsignal(Route.ri_mutex);\t\t\/* \u91ca\u653e\u4e92\u65a5\u91cf*\/
\n\treturn OK;
\n}<\/p>\n

\u91ca\u653e\u7ed3\u70b9\u7528\u7684,\u6ca1\u4ec0\u4e48\u53ef\u8bf4\u7684,\u5c31\u662f\u4f7f\u7528\u4e92\u65a5\u91cf,\u8c03\u7528\u4e00\u4e2a\u5b8f
\n\/* rtfree.c – rtfree *\/<\/p>\n

#include
\n#include
\n#include <\/p>\n

\/*————————————————————————
\n * rtfree – remove one reference to a route
\n *————————————————————————
\n *\/
\nint
\nrtfree(struct route *prt)
\n{
\n\tif (!Route.ri_valid)
\n\t\treturn SYSERR;
\n\twait(Route.ri_mutex);
\n\tRTFREE(prt);
\n\tsignal(Route.ri_mutex);
\n\treturn OK;
\n}<\/p>\n

8. IP\u9009\u9879\u5904\u7406
\n\u6ca1\u505a\u4ec0\u4e48\u5de5\u505a,\u53ea\u662f\u5206\u6790\u4e86\u4e00\u4e0bIP\u9996\u90e8\u4e2d\u9009\u9762\u957f\u5ea6\u516b\u4f4d\u7ec4\u7684\u4fe1\u606f
\n\/* ipdoopts.c – ipdoopts *\/<\/p>\n

#include
\n#include
\n#include <\/p>\n

\/*————————————————————————
\n * ipdoopts – do gateway handling of IP options
\n *————————————————————————
\n *\/
\nint
\nipdoopts(struct netif *pni, struct ep *pep)
\n{
\n\treturn OK;\t\/* not implemented yet *\/
\n}<\/p>\n

\/* ipdstopts.c – ipdstopts *\/<\/p>\n

#include
\n#include
\n#include <\/p>\n

\/*————————————————————————
\n * ipdstopts – do host handling of IP options
\n *————————————————————————
\n *\/
\nint
\nipdstopts(struct netif *pni, struct ep *pep)
\n{
\n\tstruct\tip\t*pip = (struct ip *)pep->ep_data;
\n\tu_char\t\t*popt, *popend;
\n\tint\t\tlen;<\/p>\n

\tif (IP_HLEN(pip) == IPMHLEN)
\n\t\treturn OK;
\n\tpopt = pip->ip_data;
\n\tpopend = (u_char *)&pep->ep_data[IP_HLEN(pip)];<\/p>\n

\t\/* NOTE: options not implemented yet *\/<\/p>\n

\t\/* delete the options *\/
\n\tlen = pip->ip_len-IP_HLEN(pip);\t\/* data length\t*\/
\n\tif (len)
\n\t\tmemcpy(pip->ip_data, &pep->ep_data[IP_HLEN(pip)], len);
\n\tpip->ip_len = IPMHLEN + len;
\n\tpip->ip_verlen = (pip->ip_verlen&0xf0) | IP_MINHLEN;
\n\treturn OK;
\n}<\/p>\n

\u95ee\u9898:rtdel\u8c03\u7528rtfree\u800c\u4e0d\u662f\u4f7f\u7528\u5b8f RTFREE,\u7ed3\u679c\u4f1a\u600e\u4e48\u6837? \u4f1a\u53d1\u751f\u6b7b\u9501<\/p>\n","protected":false},"excerpt":{"rendered":"

1 \u5f15\u8a00 \u8ba8\u8bba\u9009\u62e9\u8def\u7531\u7684\u7ec6\u8282\uff0c\u9009\u8def\u8868\u7684\u7ed3\u6784\uff0c\u4ee5\u53ca\u5b9e\u73b0\u7b97\u6cd5\uff0c\u8def\u7531\u5982\u4f55\u4f7f\u7528\u5b50\u7f51\u63a9\u7801\uff0c\u5982\u4f55\u533a\u5206\u7f51\u7edc\u8def\u7531\u5b50\u7f51\u8def\u7531\u4ee5\u53ca\u4e3b […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,5,14],"tags":[],"class_list":["post-598","post","type-post","status-publish","format-standard","hentry","category-linux","category-linux-c","category-14"],"_links":{"self":[{"href":"https:\/\/www.kumouse.com\/index.php?rest_route=\/wp\/v2\/posts\/598","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.kumouse.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kumouse.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kumouse.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kumouse.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=598"}],"version-history":[{"count":0,"href":"https:\/\/www.kumouse.com\/index.php?rest_route=\/wp\/v2\/posts\/598\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.kumouse.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=598"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kumouse.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=598"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kumouse.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=598"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}