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Date: Wed, 31 Jan 2007 03:50:56 -0800 From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: [Bugme-new] [Bug 7909] New: malfunction of udp_get_port() in wildcard ports assigning http://bugzilla.kernel.org/show_bug.cgi?id=7909 Summary: malfunction of udp_get_port() in wildcard ports assigning Kernel Version: 2.6.19 Status: NEW Severity: normal Owner: [EMAIL PROTECTED] Submitter: [EMAIL PROTECTED] CC: [EMAIL PROTECTED] Most recent kernel where this bug did *NOT* occur: 2.6.18.4 Distribution: Debian Hardware Environment: PCs x86-64 and i686 Software Environment: Problem Description: repeated binding of datagram sockets to some IP with wildcard port fails after ~three hundred iterations with errno EADDRINUSE. List of really assigned ports looks strangely: ...PORT[128-port-numbers-gap]PORT[128-port-numbers-gap]... Steps to reproduce: See code: #include <stdio.h> #include <netinet/in.h> #include <sys/socket.h> #include <sys/errno.h> int main(int argc, char **argv) { int iut_s; int retval; struct sockaddr_in servaddr, cliaddr; socklen_t namelen; char addr_buf[16]; int i; /* Read command line arguments */ if (argc != 2) { printf("\nuse pco_iut <local IP>\n"); return -1; } memset(&servaddr, 0, sizeof(servaddr)); servaddr.sin_family = AF_INET; inet_pton(AF_INET, argv[1], &servaddr.sin_addr); servaddr.sin_port = 0; for (i = 0; i < 1024; i++) { if ( (iut_s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { printf("\nFailed to create socket No %d error %d\n", i + 1, errno); return -1; } if (bind(iut_s,(struct sockaddr *) &servaddr, sizeof(servaddr)) != 0) { printf("\nFailed to bind socket No %d error %d\n", i + 1, errno); return -1; } namelen = sizeof(cliaddr); if (getsockname(iut_s, (struct sockaddr *)&cliaddr, &namelen) != 0) { printf("\ngetsockname() error errno %d\n", errno); return -1; } else { inet_ntop(AF_INET, &cliaddr.sin_addr, addr_buf, 16); printf("\nBound to %s:%d\n", addr_buf, ntohs(cliaddr.sin_port)); } } return 0; } The reason of this issue is IMHO in udp_get_port() function which was added in 2.6.19 version to replace udp_v4_get_port() in older versions. In ugp_get_port() we see the strange piece of code ................................................................. size = 0; sk_for_each(sk2, node, head) if (++size < best_size_so_far) { best_size_so_far = size; best = result; } } result = best; for(i = 0; i < (1 << 16) / UDP_HTABLE_SIZE; i++, result += UDP_HTABLE_SIZE) { .......................................................................... which means that sk_for_each(...) iteration is repeated only once. No such problem in older kernels where the similar piece of code in udp_v4_get_port() looks like .......................................................................... size = 0; sk_for_each(sk2, node, list) if (++size >= best_size_so_far) goto next; best_size_so_far = size; best = result; next:; } result = best; for(i = 0; i < (1 << 16) / UDP_HTABLE_SIZE; i++, result += UDP_HTABLE_SIZE) { .......................................................................... ------- You are receiving this mail because: ------- You are on the CC list for the bug, or are watching someone who is. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
