From 30d33913cb2d8e895ebf1c79595a0ebf901d925b Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Tue, 10 Jun 2014 00:35:52 +0200 Subject: [PATCH] simplify memory management for dns answers: use a blob_buf to cache entries Signed-off-by: Felix Fietkau --- dns.c | 71 +++++++++++++++++++++++++++------------------------------- util.c | 11 --------- util.h | 2 -- 3 files changed, 33 insertions(+), 51 deletions(-) diff --git a/dns.c b/dns.c index 9c7b7de..fc93f4a 100644 --- a/dns.c +++ b/dns.c @@ -40,6 +40,7 @@ #include "interface.h" static char name_buffer[MAX_NAME_LEN + 1]; +static struct blob_buf ans_buf; const char* dns_type_string(uint16_t type) @@ -112,25 +113,29 @@ struct dns_reply { char *buffer; }; -#define MAX_ANSWER 8 -static struct dns_reply dns_reply[1 + (MAX_ANSWER * 3)]; static int dns_answer_cnt; void dns_init_answer(void) { dns_answer_cnt = 0; + blob_buf_init(&ans_buf, 0); } void dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength) { - struct dns_reply *a = &dns_reply[dns_answer_cnt]; - if (dns_answer_cnt == MAX_ANSWER) - return; - a->rdata = memdup(rdata, rdlength); - a->type = type; - a->rdlength = rdlength; + struct blob_attr *attr; + struct dns_answer *a; + + attr = blob_new(&ans_buf, 0, sizeof(*a) + rdlength); + a = blob_data(attr); + a->type = cpu_to_be16(type); + a->class = cpu_to_be16(1); + a->ttl = cpu_to_be32(announce_ttl); + a->rdlength = cpu_to_be16(rdlength); + memcpy(a + 1, rdata, rdlength); + dns_answer_cnt++; } @@ -138,9 +143,11 @@ void dns_send_answer(struct interface *iface, const char *answer) { uint8_t buffer[256]; + struct blob_attr *attr; struct dns_header h = { 0 }; struct iovec *iov; - int len, i; + int answer_len, rem; + int n_iov = 0; if (!dns_answer_cnt) return; @@ -148,44 +155,32 @@ dns_send_answer(struct interface *iface, const char *answer) h.answers = __cpu_to_be16(dns_answer_cnt); h.flags = __cpu_to_be16(0x8400); - iov = alloca(sizeof(struct iovec) * ((dns_answer_cnt * 3) + 1)); - iov[0].iov_base = &h; - iov[0].iov_len = sizeof(struct dns_header); - - for (i = 0; i < dns_answer_cnt; i++) { - struct dns_answer *a = &dns_reply[i].a; - int id = (i * 3) + 1; + iov = alloca(sizeof(struct iovec) * ((dns_answer_cnt * 2) + 1)); - memset(a, 0, sizeof(*a)); - a->type = __cpu_to_be16(dns_reply[i].type); - a->class = __cpu_to_be16(1); - a->ttl = __cpu_to_be32(announce_ttl); - a->rdlength = __cpu_to_be16(dns_reply[i].rdlength); + iov[n_iov].iov_base = &h; + iov[n_iov].iov_len = sizeof(struct dns_header); + n_iov++; - len = dn_comp(answer, buffer, sizeof(buffer), NULL, NULL); - if (len < 1) - return; + answer_len = dn_comp(answer, buffer, sizeof(buffer), NULL, NULL); + if (answer_len < 1) + return; - dns_reply[i].buffer = iov[id].iov_base = memdup(buffer, len); - iov[id].iov_len = len; + blob_for_each_attr(attr, ans_buf.head, rem) { + struct dns_answer *a = blob_data(attr); - iov[id + 1].iov_base = a; - iov[id + 1].iov_len = sizeof(struct dns_answer); + iov[n_iov].iov_base = buffer; + iov[n_iov].iov_len = answer_len; + n_iov++; - iov[id + 2].iov_base = dns_reply[i].rdata; - iov[id + 2].iov_len = dns_reply[i].rdlength; + iov[n_iov].iov_base = blob_data(attr); + iov[n_iov].iov_len = blob_len(attr); + n_iov++; - DBG(1, "A <- %s %s\n", dns_type_string(dns_reply[i].type), answer); + DBG(1, "A <- %s %s\n", dns_type_string(be16_to_cpu(a->type)), answer); } - if (interface_send_packet(iface, iov, (dns_answer_cnt * 3) + 1) < 0) + if (interface_send_packet(iface, iov, n_iov) < 0) fprintf(stderr, "failed to send question\n"); - - for (i = 0; i < dns_answer_cnt; i++) { - free(dns_reply[i].buffer); - free(dns_reply[i].rdata); - } - dns_answer_cnt = 0; } static int diff --git a/util.c b/util.c index e68e9c9..eeba305 100644 --- a/util.c +++ b/util.c @@ -75,14 +75,3 @@ void get_hostname(void) snprintf(mdns_hostname, sizeof(mdns_hostname), "%s", utsname.nodename); snprintf(mdns_hostname_local, sizeof(mdns_hostname_local), "%s.local", utsname.nodename); } - -void* -memdup(const void *d, int l) -{ - void *r = malloc(l); - if (!r) - return NULL; - memcpy(r, d, l); - return r; -} - diff --git a/util.h b/util.h index aaa2bd1..1a01fcc 100644 --- a/util.h +++ b/util.h @@ -29,8 +29,6 @@ extern uint8_t mdns_buf[MDNS_BUF_LEN]; extern char mdns_hostname[HOSTNAME_LEN]; extern char mdns_hostname_local[HOSTNAME_LEN + 6]; -void *memdup(const void *d, int l); - extern void get_hostname(void); extern uint32_t rand_time_delta(uint32_t t); -- 2.30.2